I've been using IPTV services for the better part of 7 years now with Kodi, Plex, and now Channels DVR.
I'm not going to get into debates about legalities or sustainability, but I will say this, I have been very fortunate because I have been using the same IPTV service provider for three years now and it is still going strong.
So what service is it then? Sounds like it is a good service. GitHub does not offer paid iptv services there have free open source or public access links
Funny u mention GitHub... this was a recent thread
Many users here, my self included, do use Custom Channels feature and .m3u to add services like Pluto, Samsung, LG, Plex etc.
Please take IPTV talk elsewhere. We don't test Channels DVR with IPTV so it may work or there may be weird bugs.