the underlying nghttp2 version in play.
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@
1904273 13f79535-47bb-0310-9956-
ffa450edef68
'rfc7540' is the original HTTP/2 RFC, 'rfc9113' is the updated version that
disallows leading and trialing spaces in fields.
</p><p>
- Use 'highest' to use always the highest strictness checks available.
+ Use 'highest' to apply the highest strictness checks available. This
+ depends on the nghttp2 library version used. 'rfc9113' is available
+ from nghttp2 v1.50.0 and onward only. When building with previous
+ versions, this setting has no effect.
</p>
</usage>
</directivesynopsis>