<preference> specification for Prefers is misleading -- _at least_ one preference is required (1# for ABNF as per the RFC) #42535
Description
MDN URL
https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Prefer
What specific section or headline is this issue about?
No response
What information was incorrect, unhelpful, or incomplete?
The RFC says 1# which means "at least one instance of".
Header values like foo=1, bar=2 are permitted, with foo=1 and bar=2 being two distinct preferences, hence <preference> in MDN is misleading -- in the very least an improvement can be <preference>... although I am not sure what's the convention to communicate values in a list and how HTTP kind of facilitates such lists using multiple headers with the same name in a single request.
What did you expect to see?
Should say <preference> [ "," <preference> ]... or some such (I can't tell for sure what syntax convention MDN uses).
Do you have any supporting links, references, or citations?
No response
Do you have anything more you want to share?
No response
MDN metadata
Page report details
- Folder:
en-us/web/http/reference/headers/prefer - MDN URL: https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Prefer
- GitHub URL: https://github.com/mdn/content/blob/main/files/en-us/web/http/reference/headers/prefer/index.md
- Last commit: ad5b5e3
- Document last modified: 2025-07-04T01:10:07.000Z