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+++ b/README.md
@@ -2,6 +2,12 @@
 
 This is a **community-driven** list of known passkey provider AAGUIDs to assist with naming passkeys in end user passkey management interfaces (e.g. account settings). **It is not intended to be used for any other purpose** and **_could go away at any time_**. 
 
+> [!IMPORTANT]  
+> When this list is officially retired at some point in the future, the contents of both `aaguid.json` and `combined_aaguid.json` will be removed, **leaving an empty object**.
+>
+> It is **_highly_** recommended that you add some code that checks for an empty object after fetching the document (ex: `Object.keys(aaguid).length === 0`), and notifying the appropriate team(s). This README will also be updated with details.
+
+
 This does not replace [FIDO's Metadata Service (MDS)](https://fidoalliance.org/metadata/), which should continue to be used for all authoritative security details about FIDO authenticators. Some AAGUIDs in this list may not appear in FIDO MDS.
 
 ## Schema