diff --git a/data/core.yaml b/data/core.yaml
index 0e102c74f..80b75218a 100644
--- a/data/core.yaml
+++ b/data/core.yaml
@@ -382,7 +382,7 @@ en:
     switch: Switch back to this background
     custom: Custom
     custom_button: Edit custom background
-    custom_prompt: "Enter a tile URL template. Valid tokens are:\n   - {zoom}/{z}, {x}, {y} for Z/X/Y tile scheme\n   - {ty} for flipped TMS-style Y coordinates\n   - {u} for quadtile scheme\n   - {switch:a,b,c} for DNS server multiplexing\n\nExample:\n{example}"
+    custom_prompt: "Enter a tile URL template. Valid tokens are:\n   - {zoom} or {z}, {x}, {y} for Z/X/Y tile scheme\n   - {-y} or {ty} for flipped TMS-style Y coordinates\n   - {u} for quadtile scheme\n   - {switch:a,b,c} for DNS server multiplexing\n\nExample:\n{example}"
     overlays: Overlays
     imagery_source_faq: Imagery Info / Report a Problem
     reset: reset
diff --git a/dist/locales/en.json b/dist/locales/en.json
index c008d91c2..f5fab54ae 100644
--- a/dist/locales/en.json
+++ b/dist/locales/en.json
@@ -471,7 +471,7 @@
             "switch": "Switch back to this background",
             "custom": "Custom",
             "custom_button": "Edit custom background",
-            "custom_prompt": "Enter a tile URL template. Valid tokens are:\n   - {zoom}/{z}, {x}, {y} for Z/X/Y tile scheme\n   - {ty} for flipped TMS-style Y coordinates\n   - {u} for quadtile scheme\n   - {switch:a,b,c} for DNS server multiplexing\n\nExample:\n{example}",
+            "custom_prompt": "Enter a tile URL template. Valid tokens are:\n   - {zoom} or {z}, {x}, {y} for Z/X/Y tile scheme\n   - {-y} or {ty} for flipped TMS-style Y coordinates\n   - {u} for quadtile scheme\n   - {switch:a,b,c} for DNS server multiplexing\n\nExample:\n{example}",
             "overlays": "Overlays",
             "imagery_source_faq": "Imagery Info / Report a Problem",
             "reset": "reset",