Drop the phantom <basename>/ level for flat-layout installs (profileDir == root), say "entries" not "files" (count is per source path), and add ZipDir/Unzip (>1MB, empty, Zip-Slip) + flat-layout tests.
Bundles each browser's decryption-relevant files + Local State into a <browser-key>/<User Data> zip (forward-slash entries) for cross-host restore.