Android supports both Chromium-based and Firefox-based browsers since long now.
While those browsers have full support for HTTP/SOCKS proxies under all other OSes (Linux, OSX and even Windows), they are lacking it completely under Android. There's no setting at all to configure one.
I can easily configure a SOCKSv5 proxy on my Android device with, say,
ssh -D to be used over whatever connections I have (wifi, ethernet, mobile data...), but I cannot use it with my browsers.
There's some system-wide support when you configure wifi, but that's not what I talk about. I mean the good ol' application-level proxy support. I don't want to send all traffic through a proxy, but just that for a specific browser on demand.
For the curious, I am asking this because I need and can compare results on my landline Internet link, but I cannot do the same on my mobile one.
Please, forget about VPNs which are also system-wide solutions like wifi proxies. I need to configure a proxy on a per-browser basis, just like I can do on a PC, and not a VPN.
So, why this lack?