https://lists.busybox.net/pipermail/busybox-cvs/2009-September/029969.html
[git commit master] tar: accept spaces at the end of header fields (compat)
at the endgit commitheader fieldsmastertar
https://www.rfc-editor.org/info/rfc4021/
RFC 4021: Registration of Mail and MIME Header Fields | RFC Editor
Mar 18, 2005 - This document defines the initial IANA registration for permanent mail and MIME message header fields, per RFC 3864. [STANDARDS-TRACK]
header fieldsrfcregistrationmailmime
https://merginit.com/reference/http/status-431
HTTP 431 Request Header Fields Too Large - MerginIT Reference
Use 431 when cookies or custom headers exceed configured limits.
request headerhttpfieldslargereference
https://buddypress.org/support/reply/258905/
Reply To: Adding xprofile fields to activity header ยท BuddyPress.org
reply toaddingxprofilefieldsactivity