mod_pagespeed#
Google's speed up module for Apache httpd (and nginx).
See https://developers.google.com/speed/pagespeed/
Mobile forward proxy#
Proxy settings on Mobile is not always straightforward, it depends on the distribution, the stock ROMs often have their proxy page orphaned so you cannot get to it, unless you install something like "Proxy Settings", that provide a way to get to that page.
On most custom ROMs you can set your proxy settings, but that doesnt mean all apps use it.
On my (ancient) HTC HD2 with 
Mobile settings :
- Dolphin does not properly set http headers for http/1.1 and https...more
- Firefox proxy settings via about:config.........more
Settings apache module
Security settings