It's a pidgin-gnome3 integration extension.
"GNOME3 comes with Telepathy/Empathy integration. However, I'm mainly a Pidgin user because Telepathy/Empathy lacks of per-account proxy settings. I always force my IMs to go through a proxy in VPN regardless where I am, but not for other apps, so telepathy/empathy is out of the equation."
Created attachment 274755 [details]
Created attachment 274759 [details]
https://developer.pidgin.im/ticket/13867 seems somewhat related. If I understand it right than applying those patches will upgrade proxy support in Pidgin with use of Gnome3 and than there would be no need for gnome-shell-extensions-pidgin in the future, right?
Anyway might be worth you check it out