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internals: update for macOS 12.4 Monterey

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Michael Roitzsch
2022-06-06 21:45:17 +02:00
parent 909ec8a160
commit 40b2576d55
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internals.tsv
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@@ -1,6 +1,7 @@
Term Description
1TR One True Recovery; booting into macOS recovery on Apple Silicon by holding the power button to verify physical presence; enables interaction with SEP to change Boot Policy
AA Apple account
AA Apple Archive, see also Apple Encrypted Archive; command line tools: aa, aea, compression_tool
AAC Automatic Assessment Configuration; AutomaticAssessmentConfiguration.framework; puts device in a locked mode for exam-style test applications
AAT Apple Advanced Typography; font format and rendering engine
Accounts launchd service: com.apple.accountsd; /System/Library/Accounts
@@ -10,7 +11,6 @@ Acoustic ID Siri feature to recognize songs
Activation cryptographic check-in with iCloud to lock devices reported by the user as lost; verified by iBoot; MobileActivationMacOS.framework; launchd service: com.apple.mobileactivationd; servers: humb.apple.com, albert.apple.com
Activity jobs, coarse-grained work units of applications; tracked by the system across XPC, bears a QoS class for scheduling; low-level mechanism not to be confused with User Activity
AE Apple Events; messaging system to invoke application functionality; CoreServices.framework/AE.framework; launchd services: com.apple.coreservices.appleevents, com.apple.AEServer (AE over network)
AEA Apple Encrypted Archive; command line tool: aea
AGC Apple Graphics Control, management of multiple displays and display port connections; launchd service: com.apple.displaypolicyd
AIR Apple Intermediate Representation; synthetic bytecode architecture target for GPU binary toolchain
ALF Application-Level Firewall, launchd service: com.apple.alf (socketfilterfw)
@@ -38,11 +38,11 @@ ASR Apple Software Restore; restore entire volumes from sources like disk images
Assertions power state management allowing applications to prevent sleeping; launchd service: com.apple.powerd; command line tools: caffeinate, pmset
Assessment checking of System Policy; term also used for AAC
Asset Cache discretionary caching server for Mobile Assets, Packages, iOS updates, App Store content, ODR, MMCS data; launchd services: com.apple.AssetCache.builtin, com.apple.AssetCacheLocatorService, com.apple.AssetCacheManagerService, com.apple.AssetCacheTetheratorService; command line tools: AssetCacheLocatorUtil, AssetCacheManagerUtil, AssetCacheTetheratorUtil
Assistant Siri; dictation and semantic understanding, Intent is communicated to and enacted on the client, uses TTS; /System/Library/Assistant, AssistantServices.framework; server: *.siri.apple.com
Assistant Siri; dictation and semantic understanding, Intent is communicated to and enacted on the client, uses TTS for output, Snippets to embed mini UIs into responses; /System/Library/Assistant, /System/Library/Snippets, AssistantServices.framework; server: *.siri.apple.com
ATS App Transport Security, sandbox mechanism only allowing TLS-secured connections
ATSUI Apple Type Services for Unicode Imaging; rendering engine superseded by CoreText.framework, font management; ApplicationServices.framework/ATS.framework; launchd service: com.apple.xtyped (fontd); command line tools: atsutil
ATT App Tracking Transparency; apps declare user tracking on app store
Attestation cryptographic proof of a genuine SEP; used for web authentication and app attestation; DeviceCheck.framework; online service signs a GID-based challenge response? used to pair RemoteXPC channel? stripped down variant used to securely identify Touch ID keyboards
Attestation cryptographic proof of a genuine SEP; used for web authentication and app attestation; DeviceCheck.framework; SEP responds to challenge using hardware-key (GID, PKA), online service verifies; used to pair Touch ID keyboards, used to pair RemoteXPC channel?
Authorization discretionary access control policies for high-level services; similar to PAM; policy stored in /var/db/auth.db
Avatar Memoji and Animoji (face tracking); AvatarKit.framework
AVB Audio Video Bridging, low-latency audio over Ethernet; launchd service: com.apple.avbdeviced; command line tool: avbdiagnose, avbutil
@@ -64,9 +64,10 @@ CAML Core Animation Markup Language; XML file format for layers, shapes and anim
Carousel derivative of SpringBoard for Watch home screen, watch face, and notification center
Celestial media streaming used by ReplayKit for game broadcasts; Celestial.framework
Certificates validity checked using CRLs, OCSP stapling, and transparency logs; /System/Library/Security/Certificates.bundle; launchd services: com.apple.trustd, com.apple.trustd.agent, com.apple.ocspd; command line tool: crlrefresh
Circle cryptographic primitive to exchange public keys of all trusted devices of one user, signed by all Circle peers; iCloud identity keypair as an additional Circle peer, triggers countersigning from all trusted devices, private key synced across all trusted devices, new devices can pull this key from Secure Backup to join the Circle; used by CKKS; KeychainCircle.framework; command line tools: tpctl, otctl (Octagon trust is newer?)
CKKS CloudKit Key Sync, end-to-end secure syncing for credentials, seeded by Circle, transferred items stored ephemerally using OTR protocol; currently includes ApplePay, AutoUnlock, CreditCards, DevicePairing, Engram, Health, Home, Manatee, SOS, WiFi and other keys; launchd service: com.apple.secd; command line tool: ckksctl
Classroom launchd service: com.apple.studentd
CHIP Connected Home over IP; Matter; integrated into HomeKit; CHIP.framework
Circle cryptographic primitive to exchange public keys of trusted devices of a user, signed by Circle peers; iCloud identity added as additional Circle peer, private key synced across all trusted devices, new devices can pull this key from Secure Backup to join the Circle; per-device Circles stored in CKKS for two-factor accounts (Octagon); KeychainCircle.framework; command line tools: tpctl, otctl (Octagon)
CKKS CloudKit Key Sync, end-to-end secure syncing for credentials, seeded by Circle; currently includes ApplePay, AutoUnlock, CreditCards, DevicePairing, Engram, Health, Home, Manatee, SOS, WiFi and other keys; launchd service: com.apple.secd; command line tool: ckksctl
Classroom school teachers can create assignments for student iPads and track progress in Schoolwork app; ClassKit.framework; launchd service: com.apple.studentd
Cloud Pairing part of Alloy, Bluetooth out-of-band pairing over iCloud for Continuity; launchd service: com.apple.BTServer.cloudpairing (cloudpaird)
CMAS Commerial Mobile Alert System, now known as Wireless Emergency Alerts (WEA)
Commpage user-mapped kernel data, like vdso/vsyscall on Linux; mapped at 0x7fffffe00000
@@ -110,6 +111,7 @@ FDE Full Disk Encryption, FileVault; command line tool: fdesetup, sysadminctl
FDR Factory Data/Device Reset? ensures that no downgrades are performed? servers: skl.apple.com, gg.apple.com; /System/Library/FDR
Feldspar Apple News; Silex.framework
FiDES Fi? Distributed Evaluation Service? aggregates Differential Privacy data for unlinkability? maybe private federated learning? used for emoji, Suggestions, Dictation; /System/Library/DistributedEvaluation; DistributedEvaluation.framework; server: fides-pol.apple.com
File Provider infrastructure and extension system for syncing with cloud providers; placeholder files based on SF_DATALESS attribute in APFS; FileProvider.framework; locally stored in ~/Library/CloudStorage; command line tool: fileproviderctl
Find My … location sharing by explicitly querying devices remotely or collateral beacon detection using Search Party; FMCore.framework, FMF.framework; launchd service: com.apple.icloud.fmfd (find my friends)
Firmlink bi-directional non-symbolic link between the read-only system volume and the data volume, additional symlinks and mountpoints in the root directory are virtually allocated; /usr/share/firmlinks, /etc/synthetic.conf
Focus restriction modes for notification presentation; Focus.framework, DoNotDisturb.framework; local settings in ~/Library/DoNotDisturb
@@ -163,7 +165,7 @@ LKDC Local Key Distribution Center, Kerberos on client machines
LSM Latent Semantic Mapping, text analysis, used for spam filtering, command line tool: lsm
Mac Buddy historic name for Setup Assistant
MAC Policy Mandatory Access Control subsystem in XNU, based on TrustedBSD, implements policy hooks for restricted kernel operations; current policies: AMFI, Seatbelt, Quarantine, CSR
Machine Learning Vision.framework, Espresso.framework, Futhark.framework, PhotoAnalysis.framework; launchd service: com.apple.mediaanalysisd
Machine Learning Vision.framework, Espresso.framework, Futhark.framework, PhotoAnalysis.framework; used for Live Text and Visual Lookup; launchd service: com.apple.mediaanalysisd
Madrid iMessage; /System/Library/Messages
Manatee PCS key for some CloudKit containers are synced via CKKS, so data is unreadable to Apple (credential management codenames: Plesio, Stingray, Cuttlefish)
Mangrove transfering UI tiles over XPC; Mangrove.framework, IOSurface.framework
@@ -226,7 +228,7 @@ RAOP Remote Audio Output Protocol, AirPlay; Bonjour service: _raop._tcp
Rapport device pairing by proximity using Alloy, with PIN entry, or using iCloud; once paired, devices can access services; used for HomeKit, HomePod, AirPlay, Home Sharing, SideCar; Rapport.framework; launchd service: com.apple.rapportd; Bonjour service: _companion-link._tcp
Recents recently used items (not files) in various applications, synced with Synced Defaults; CoreRecents.framework, /System/Library/Recents; launchd service: com.apple.recentsd
Relevance Engine backend for Siri suggestions (for example of Siri Shortcuts), Widget smart stacks (also Siri watch face); consumes Duet knowledge and app-provided timelines with relevance hints; /System/Library/RelevanceEngine; launchd service: com.apple.relevanced
Remote Pairing Mobile Device pairing without wired connection; RemotePairingDevice.framework; launchd service: com.apple.dt.remotepairingdeviced; Bonjour services: _remotepairing._tcp, _remotepairing-manual-pairing._tcp
Remote Pairing Mobile Device pairing without wired connection; RemotePairingDevice.framework; Bonjour services: _remotepairing._tcp, _remotepairing-manual-pairing._tcp
RemoteXPC connection to a non-SoC-integrated SEP like Bridge; uses HTTP/2 over a network interface, Bridge connected over USB, secured using Attestation; RemoteServiceDiscovery.framework, TrustedAccessory.framework; launchd service: com.apple.remoted, com.apple.tracd; command line tool: remotectl
Revisions document autosave and auto-versioning; stored in .DocumentRevisions-V100; GenerationalStorage.framework; launchd service: com.apple.revisiond
Routine frequently visited locations on iOS, interacts with Duet; launchd service: com.apple.routined
@@ -258,7 +260,7 @@ Skywalk network subsystem in XNU, links together actual technologies (Bluetooth,
SLC System-Level Cache, architectural feature of Apple Silicon; cache located within SoC at controllers for external DRAM, serves all compute units and stages transfers between them
Social Gaming Game Center; multiplayer gaming services on top of CloudKit, shared storage and low-latency multicast for multiplayer sessions; launchd service: com.apple.gamed
Sock Puppet Watch interaction that requires Companion device
SOS Secure Object Sync; syncing backend for iCloud Keychain, not to be confused with the emergency call feature; transferred items previously staged in Synced Defaults, now uses CKKS; launchd services: com.apple.secd (access to local keychain), com.apple.security.cloudkeychainproxy3 (connects to Synced Defaults), com.apple.security.keychain-circle-notification
SOS Secure Object Sync; syncing backend for iCloud Keychain, not to be confused with the emergency call feature; transferred items previously staged in Synced Defaults, for two-factor accounts in CKKS; launchd services: com.apple.secd (access to local keychain), com.apple.security.cloudkeychainproxy3 (connects to Synced Defaults), com.apple.security.keychain-circle-notification
SPI System Private Interface; /System/Library/PrivateFrameworks
SpringBoard iOS home screen; like Dock (Launchpad, Mission Control, desktop picture), Control Center, SystemUIServer (menu extras icons), loginwindow (lock screen), and WindowServer (compositor) on macOS; /System/Library/CoreServices/SpringBoard.app, /Applications/PreBoard.app, BaseBoard.framework, FrontBoard.framework, SplashBoard.framework; launchd service: com.apple.backboardd (compositor)
SPRR Shadow Permission Remap Register? feature of Apple Silicon to dynamically reintepret page permissions
@@ -269,7 +271,7 @@ Stark CarPlay
Stockholm Secure Element in Apple SoCs, a processor running crypto protocols on keys it protects; used for Apple Pay and Car Key; related codenames: Icefall, Warsaw
Storage Management freeing up disk space by managing bulky items; UI in System Information.app; StorageManagement.framework; launchd service: com.apple.diskspaced; extension point: com.apple.storagemanagement; extends Cache Delete service
Suggestions semantic analysis of mails and websites to suggest contacts, calendar events and the like; launchd services: com.apple.suggestd, com.apple.reversetemplated; custom JavaScript parsers in /System/Library/AssetsV2/com_apple_MobileAsset_CoreSuggestions
Symbols debug symbols for backtraces; CoreSymbolication.framework; launchd services: com.apple.coresymbolicationd; command line tools: symbols, symbolscache
Symbols debug symbols for backtraces; CoreSymbolication.framework; launchd services: com.apple.coresymbolicationd; command line tools: atos, symbols, symbolscache
Symptoms network diagnostics; Symptoms.framework; /var/networkd/db/netusage.sqlite; launchd service: com.apple.symptomsd (invoked by kernel through host special port 27)
Synced Defaults simple key-value store for applications, no user control over data; can use iCloud key-value backend (old) or Manatee container (new, marked as com.apple.kvs) as storage; launchd service: com.apple.syncdefaultsd; locally stored in ~/Library/SyncedPreferences
System Configuration SystemConfiguration.framework; launchd service: com.apple.configd; command line tool: scutil
@@ -286,10 +288,10 @@ Transparency key transparency for ESS keys? Transparency.framework; launchd serv
TSS Tatsu Signing Server; online verification for firmware signatures; server: gs.apple.com
TTS Text To Speech, command line tool: say; /System/Library/Speech; synthesizer engines: MacinTalk (historic), Polyglot (phoneme-based?), Gryphon (current, DNN-based?)
TVML TV Markup Language; declarative UI language for TV apps; TVMLKit.framework
Ubiquity iCloud Drive; codename Bladerunner, uses CloudKit; CloudDocs.framework; command line tools: fileproviderctl; launchd service: com.apple.bird (iclouddrive-agent); locally stored in ~/Library/Mobile Documents (was supposed to move to Library/CloudStorage/iCloud Drive and iclouddrivectl but this was reverted)
Ubiquity iCloud Drive; codename Bladerunner, uses CloudKit; CloudDocs.framework; launchd service: com.apple.bird; locally stored in ~/Library/Mobile Documents (was supposed to move to Library/CloudStorage/iCloud Drive but this was reverted)
UID unique ID key, used as root key for cryptographic subsystems, generated during manufacturing by SEP and fused into hardware, only accessible by SEP
Unified Logging system-wide logging and Activity tracking; launchd service: com.apple.logd, com.apple.diagnosticd; command line tool: log; /dev/oslog; data stored in /var/db/diagnostics, support files in /var/db/uuidtext
User Activity abstraction behind deep-linking into apps with structured context data (people, places); used for Universal Links (with schema.org on websites), Handoff, Parsec, Siri Shortcuts, Proactive; UserActivity.framework; launchd service: com.apple.coreservices.useractivityd
User Activity abstraction for deep-linking into apps with structured context (people, places); used for Universal Links (schema.org on websites), Handoff, Parsec (app links in search), Siri Shortcuts, Quick Note (context awareness), Proactive; UserActivity.framework; launchd service: com.apple.coreservices.useractivityd
User Notifications user interface for notification center; launchd service: com.apple.usernoted
UTI Uniform Type Identifiers; system for document types; file extensions and MIME types are mapped to UTIs, UTIs form a conformance graph, apps register their UTIs with Launch Services; /System/Library/CoreServices/CoreTypes.bundle; also Apple’s hardware devices are represented as UTIs
VA Video Acceleration; AppleGVA.framework, AppleVA.framework, AppleVPA.framework
1 Term Description
2 1TR One True Recovery; booting into macOS recovery on Apple Silicon by holding the power button to verify physical presence; enables interaction with SEP to change Boot Policy
3 AA Apple account
4 AA Apple Archive, see also Apple Encrypted Archive; command line tools: aa, aea, compression_tool
5 AAC Automatic Assessment Configuration; AutomaticAssessmentConfiguration.framework; puts device in a locked mode for exam-style test applications
6 AAT Apple Advanced Typography; font format and rendering engine
7 Accounts launchd service: com.apple.accountsd; /System/Library/Accounts
11 Activation cryptographic check-in with iCloud to lock devices reported by the user as lost; verified by iBoot; MobileActivationMacOS.framework; launchd service: com.apple.mobileactivationd; servers: humb.apple.com, albert.apple.com
12 Activity jobs, coarse-grained work units of applications; tracked by the system across XPC, bears a QoS class for scheduling; low-level mechanism not to be confused with User Activity
13 AE Apple Events; messaging system to invoke application functionality; CoreServices.framework/AE.framework; launchd services: com.apple.coreservices.appleevents, com.apple.AEServer (AE over network)
AEA Apple Encrypted Archive; command line tool: aea
14 AGC Apple Graphics Control, management of multiple displays and display port connections; launchd service: com.apple.displaypolicyd
15 AIR Apple Intermediate Representation; synthetic bytecode architecture target for GPU binary toolchain
16 ALF Application-Level Firewall, launchd service: com.apple.alf (socketfilterfw)
38 Assertions power state management allowing applications to prevent sleeping; launchd service: com.apple.powerd; command line tools: caffeinate, pmset
39 Assessment checking of System Policy; term also used for AAC
40 Asset Cache discretionary caching server for Mobile Assets, Packages, iOS updates, App Store content, ODR, MMCS data; launchd services: com.apple.AssetCache.builtin, com.apple.AssetCacheLocatorService, com.apple.AssetCacheManagerService, com.apple.AssetCacheTetheratorService; command line tools: AssetCacheLocatorUtil, AssetCacheManagerUtil, AssetCacheTetheratorUtil
41 Assistant Siri; dictation and semantic understanding, Intent is communicated to and enacted on the client, uses TTS; /System/Library/Assistant, AssistantServices.framework; server: *.siri.apple.com Siri; dictation and semantic understanding, Intent is communicated to and enacted on the client, uses TTS for output, Snippets to embed mini UIs into responses; /System/Library/Assistant, /System/Library/Snippets, AssistantServices.framework; server: *.siri.apple.com
42 ATS App Transport Security, sandbox mechanism only allowing TLS-secured connections
43 ATSUI Apple Type Services for Unicode Imaging; rendering engine superseded by CoreText.framework, font management; ApplicationServices.framework/ATS.framework; launchd service: com.apple.xtyped (fontd); command line tools: atsutil
44 ATT App Tracking Transparency; apps declare user tracking on app store
45 Attestation cryptographic proof of a genuine SEP; used for web authentication and app attestation; DeviceCheck.framework; online service signs a GID-based challenge response? used to pair RemoteXPC channel? stripped down variant used to securely identify Touch ID keyboards cryptographic proof of a genuine SEP; used for web authentication and app attestation; DeviceCheck.framework; SEP responds to challenge using hardware-key (GID, PKA), online service verifies; used to pair Touch ID keyboards, used to pair RemoteXPC channel?
46 Authorization discretionary access control policies for high-level services; similar to PAM; policy stored in /var/db/auth.db
47 Avatar Memoji and Animoji (face tracking); AvatarKit.framework
48 AVB Audio Video Bridging, low-latency audio over Ethernet; launchd service: com.apple.avbdeviced; command line tool: avbdiagnose, avbutil
64 Carousel derivative of SpringBoard for Watch home screen, watch face, and notification center
65 Celestial media streaming used by ReplayKit for game broadcasts; Celestial.framework
66 Certificates validity checked using CRLs, OCSP stapling, and transparency logs; /System/Library/Security/Certificates.bundle; launchd services: com.apple.trustd, com.apple.trustd.agent, com.apple.ocspd; command line tool: crlrefresh
67 Circle CHIP cryptographic primitive to exchange public keys of all trusted devices of one user, signed by all Circle peers; iCloud identity keypair as an additional Circle peer, triggers countersigning from all trusted devices, private key synced across all trusted devices, new devices can pull this key from Secure Backup to join the Circle; used by CKKS; KeychainCircle.framework; command line tools: tpctl, otctl (Octagon trust is newer?) Connected Home over IP; Matter; integrated into HomeKit; CHIP.framework
68 CKKS Circle CloudKit Key Sync, end-to-end secure syncing for credentials, seeded by Circle, transferred items stored ephemerally using OTR protocol; currently includes ApplePay, AutoUnlock, CreditCards, DevicePairing, Engram, Health, Home, Manatee, SOS, WiFi and other keys; launchd service: com.apple.secd; command line tool: ckksctl cryptographic primitive to exchange public keys of trusted devices of a user, signed by Circle peers; iCloud identity added as additional Circle peer, private key synced across all trusted devices, new devices can pull this key from Secure Backup to join the Circle; per-device Circles stored in CKKS for two-factor accounts (Octagon); KeychainCircle.framework; command line tools: tpctl, otctl (Octagon)
69 Classroom CKKS launchd service: com.apple.studentd CloudKit Key Sync, end-to-end secure syncing for credentials, seeded by Circle; currently includes ApplePay, AutoUnlock, CreditCards, DevicePairing, Engram, Health, Home, Manatee, SOS, WiFi and other keys; launchd service: com.apple.secd; command line tool: ckksctl
70 Classroom school teachers can create assignments for student iPads and track progress in Schoolwork app; ClassKit.framework; launchd service: com.apple.studentd
71 Cloud Pairing part of Alloy, Bluetooth out-of-band pairing over iCloud for Continuity; launchd service: com.apple.BTServer.cloudpairing (cloudpaird)
72 CMAS Commerial Mobile Alert System, now known as Wireless Emergency Alerts (WEA)
73 Commpage user-mapped kernel data, like vdso/vsyscall on Linux; mapped at 0x7fffffe00000
111 FDR Factory Data/Device Reset? ensures that no downgrades are performed? servers: skl.apple.com, gg.apple.com; /System/Library/FDR
112 Feldspar Apple News; Silex.framework
113 FiDES Fi? Distributed Evaluation Service? aggregates Differential Privacy data for unlinkability? maybe private federated learning? used for emoji, Suggestions, Dictation; /System/Library/DistributedEvaluation; DistributedEvaluation.framework; server: fides-pol.apple.com
114 File Provider infrastructure and extension system for syncing with cloud providers; placeholder files based on SF_DATALESS attribute in APFS; FileProvider.framework; locally stored in ~/Library/CloudStorage; command line tool: fileproviderctl
115 Find My … location sharing by explicitly querying devices remotely or collateral beacon detection using Search Party; FMCore.framework, FMF.framework; launchd service: com.apple.icloud.fmfd (find my friends)
116 Firmlink bi-directional non-symbolic link between the read-only system volume and the data volume, additional symlinks and mountpoints in the root directory are virtually allocated; /usr/share/firmlinks, /etc/synthetic.conf
117 Focus restriction modes for notification presentation; Focus.framework, DoNotDisturb.framework; local settings in ~/Library/DoNotDisturb
165 LSM Latent Semantic Mapping, text analysis, used for spam filtering, command line tool: lsm
166 Mac Buddy historic name for Setup Assistant
167 MAC Policy Mandatory Access Control subsystem in XNU, based on TrustedBSD, implements policy hooks for restricted kernel operations; current policies: AMFI, Seatbelt, Quarantine, CSR
168 Machine Learning Vision.framework, Espresso.framework, Futhark.framework, PhotoAnalysis.framework; launchd service: com.apple.mediaanalysisd Vision.framework, Espresso.framework, Futhark.framework, PhotoAnalysis.framework; used for Live Text and Visual Lookup; launchd service: com.apple.mediaanalysisd
169 Madrid iMessage; /System/Library/Messages
170 Manatee PCS key for some CloudKit containers are synced via CKKS, so data is unreadable to Apple (credential management codenames: Plesio, Stingray, Cuttlefish)
171 Mangrove transfering UI tiles over XPC; Mangrove.framework, IOSurface.framework
228 Rapport device pairing by proximity using Alloy, with PIN entry, or using iCloud; once paired, devices can access services; used for HomeKit, HomePod, AirPlay, Home Sharing, SideCar; Rapport.framework; launchd service: com.apple.rapportd; Bonjour service: _companion-link._tcp
229 Recents recently used items (not files) in various applications, synced with Synced Defaults; CoreRecents.framework, /System/Library/Recents; launchd service: com.apple.recentsd
230 Relevance Engine backend for Siri suggestions (for example of Siri Shortcuts), Widget smart stacks (also Siri watch face); consumes Duet knowledge and app-provided timelines with relevance hints; /System/Library/RelevanceEngine; launchd service: com.apple.relevanced
231 Remote Pairing Mobile Device pairing without wired connection; RemotePairingDevice.framework; launchd service: com.apple.dt.remotepairingdeviced; Bonjour services: _remotepairing._tcp, _remotepairing-manual-pairing._tcp Mobile Device pairing without wired connection; RemotePairingDevice.framework; Bonjour services: _remotepairing._tcp, _remotepairing-manual-pairing._tcp
232 RemoteXPC connection to a non-SoC-integrated SEP like Bridge; uses HTTP/2 over a network interface, Bridge connected over USB, secured using Attestation; RemoteServiceDiscovery.framework, TrustedAccessory.framework; launchd service: com.apple.remoted, com.apple.tracd; command line tool: remotectl
233 Revisions document autosave and auto-versioning; stored in .DocumentRevisions-V100; GenerationalStorage.framework; launchd service: com.apple.revisiond
234 Routine frequently visited locations on iOS, interacts with Duet; launchd service: com.apple.routined
260 SLC System-Level Cache, architectural feature of Apple Silicon; cache located within SoC at controllers for external DRAM, serves all compute units and stages transfers between them
261 Social Gaming Game Center; multiplayer gaming services on top of CloudKit, shared storage and low-latency multicast for multiplayer sessions; launchd service: com.apple.gamed
262 Sock Puppet Watch interaction that requires Companion device
263 SOS Secure Object Sync; syncing backend for iCloud Keychain, not to be confused with the emergency call feature; transferred items previously staged in Synced Defaults, now uses CKKS; launchd services: com.apple.secd (access to local keychain), com.apple.security.cloudkeychainproxy3 (connects to Synced Defaults), com.apple.security.keychain-circle-notification Secure Object Sync; syncing backend for iCloud Keychain, not to be confused with the emergency call feature; transferred items previously staged in Synced Defaults, for two-factor accounts in CKKS; launchd services: com.apple.secd (access to local keychain), com.apple.security.cloudkeychainproxy3 (connects to Synced Defaults), com.apple.security.keychain-circle-notification
264 SPI System Private Interface; /System/Library/PrivateFrameworks
265 SpringBoard iOS home screen; like Dock (Launchpad, Mission Control, desktop picture), Control Center, SystemUIServer (menu extras icons), loginwindow (lock screen), and WindowServer (compositor) on macOS; /System/Library/CoreServices/SpringBoard.app, /Applications/PreBoard.app, BaseBoard.framework, FrontBoard.framework, SplashBoard.framework; launchd service: com.apple.backboardd (compositor)
266 SPRR Shadow Permission Remap Register? feature of Apple Silicon to dynamically reintepret page permissions
271 Stockholm Secure Element in Apple SoCs, a processor running crypto protocols on keys it protects; used for Apple Pay and Car Key; related codenames: Icefall, Warsaw
272 Storage Management freeing up disk space by managing bulky items; UI in System Information.app; StorageManagement.framework; launchd service: com.apple.diskspaced; extension point: com.apple.storagemanagement; extends Cache Delete service
273 Suggestions semantic analysis of mails and websites to suggest contacts, calendar events and the like; launchd services: com.apple.suggestd, com.apple.reversetemplated; custom JavaScript parsers in /System/Library/AssetsV2/com_apple_MobileAsset_CoreSuggestions
274 Symbols debug symbols for backtraces; CoreSymbolication.framework; launchd services: com.apple.coresymbolicationd; command line tools: symbols, symbolscache debug symbols for backtraces; CoreSymbolication.framework; launchd services: com.apple.coresymbolicationd; command line tools: atos, symbols, symbolscache
275 Symptoms network diagnostics; Symptoms.framework; /var/networkd/db/netusage.sqlite; launchd service: com.apple.symptomsd (invoked by kernel through host special port 27)
276 Synced Defaults simple key-value store for applications, no user control over data; can use iCloud key-value backend (old) or Manatee container (new, marked as com.apple.kvs) as storage; launchd service: com.apple.syncdefaultsd; locally stored in ~/Library/SyncedPreferences
277 System Configuration SystemConfiguration.framework; launchd service: com.apple.configd; command line tool: scutil
288 TSS Tatsu Signing Server; online verification for firmware signatures; server: gs.apple.com
289 TTS Text To Speech, command line tool: say; /System/Library/Speech; synthesizer engines: MacinTalk (historic), Polyglot (phoneme-based?), Gryphon (current, DNN-based?)
290 TVML TV Markup Language; declarative UI language for TV apps; TVMLKit.framework
291 Ubiquity iCloud Drive; codename Bladerunner, uses CloudKit; CloudDocs.framework; command line tools: fileproviderctl; launchd service: com.apple.bird (iclouddrive-agent); locally stored in ~/Library/Mobile Documents (was supposed to move to Library/CloudStorage/iCloud Drive and iclouddrivectl but this was reverted) iCloud Drive; codename Bladerunner, uses CloudKit; CloudDocs.framework; launchd service: com.apple.bird; locally stored in ~/Library/Mobile Documents (was supposed to move to Library/CloudStorage/iCloud Drive but this was reverted)
292 UID unique ID key, used as root key for cryptographic subsystems, generated during manufacturing by SEP and fused into hardware, only accessible by SEP
293 Unified Logging system-wide logging and Activity tracking; launchd service: com.apple.logd, com.apple.diagnosticd; command line tool: log; /dev/oslog; data stored in /var/db/diagnostics, support files in /var/db/uuidtext
294 User Activity abstraction behind deep-linking into apps with structured context data (people, places); used for Universal Links (with schema.org on websites), Handoff, Parsec, Siri Shortcuts, Proactive; UserActivity.framework; launchd service: com.apple.coreservices.useractivityd abstraction for deep-linking into apps with structured context (people, places); used for Universal Links (schema.org on websites), Handoff, Parsec (app links in search), Siri Shortcuts, Quick Note (context awareness), Proactive; UserActivity.framework; launchd service: com.apple.coreservices.useractivityd
295 User Notifications user interface for notification center; launchd service: com.apple.usernoted
296 UTI Uniform Type Identifiers; system for document types; file extensions and MIME types are mapped to UTIs, UTIs form a conformance graph, apps register their UTIs with Launch Services; /System/Library/CoreServices/CoreTypes.bundle; also Apple’s hardware devices are represented as UTIs
297 VA Video Acceleration; AppleGVA.framework, AppleVA.framework, AppleVPA.framework