Announce and document "apache2: send the right cache-control headers when available"
The following discussion from !381 (merged) should be addressed:
This will need an email to lava-announce and adjustments in files managed outside LAVA (e.g. in salt for the Harston lab). Some documentation in the simple-admin.rst may be required to explain what is in the commit message with links. (If
ProxyPreserveHost Onisn't mentioned there, that should be added too.)