Apache environment variables list?

Do the apache docs have a full list of these variables? Or is there some way that I can find out what they are in apache? The variables are things like %{Referer} and %{User-agent}.

Solution 1:

Dave from addedbytes wrote this great cheatsheet: https://www.cheatography.com/davechild/cheat-sheets/mod-rewrite/

Solution 2:

Apache HTTP Server v2.4 documentation provides expression parser variables here that includes the %{HTTP_REFERER} and %{HTTP_USER_AGENT} aspects you were seeking.

Also, keep in mind, the docs mention this and other details:

Note that the value of a variable may depend on the phase of the request processing in which it is evaluated.

A bit different but somewhat related is v2.4 documentation on environment variables that affect the Apache HTTP Server.