I posted saying I use the FUTO Keyboard as it's open source
It is not.
Even if you think that the license prohibiting commercial use makes it not open source, it certainly doesn't make it proprietary.
It does. If the license doesn't meet the OSD and the FSD, then it is proprietary, because,
“Proprietary software is another name for nonfree software.” - Categories of Free and Nonfree Software.
YDI.
Every time someone mentions XMPP I want to link this Soatok's blogpost.
Against XMPP+OMEMO