Currently, https://www.mediawiki.org/wiki/Extension:BounceHandler shows how to route a bounce back to Meidaiwki API via exim4 MTA, which is used in our production servers. No proper documentation of how to get that done in Postfix is given. I just received this email :
I just wanted to ask you if do know where this extension is installed in combination with postfix (and not exim) and/or if there is any documentation how to configure that correctly in postfix.