mod_http_oauth2: Strip unknown extra fields from client registration We shouldn't sign things we don't understand! RFC 7591 section-2 states: > The authorization server MUST ignore any client metadata sent by the > client that it does not understand (for instance, by silently removing > unknown metadata from the client's registration record during > processing). Prevents grandfathering in of unvalidated data that might become used later, especially since the 'additionalProperties' schema keyword was removed in 698fef74ce53

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summary: Log a message once per minute
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This module sends `-- MARK --` to the log once per minute. This may be
useful to give a sense of how busy the server is or see that logging and
timers are still working.