[FERN-SCRIBE] Add list of extension headers #266
Description
📝 What do you want Fern Scribe (AI Technical Writer) to do?
Add a comprehensive list of all extension headers
🔗 Link to existing Slack thread
https://buildwithfern.slack.com/archives/C0811KJCBL4/p1749843216981529
📋 Do you know of any documentation that needs to be updated?
not sure
❌ If yes, describe why that documentation is incorrect
No response
📰 Changelog Update Required
- Yes, include changelog entry
- No changelog needed
📎 Additional Context
No response