I do not know what you are exactly asking a pull request for, but you should probably be on GitHub.com 
According to Darmur, he has instructions on how to request a pull-request: Help from Volumio community for a new feature.
He replied to me and stated help. If there is a different process, I would be happy to follow it.
Hm yeah, seems a little vague, I think you have to post it in Help from Volumio community for a new feature.
I already took care of creating the pull-request, this thread can be closed or merged with the original request