Project information:
Multistreaming plugin for OBS, allows the user to stream to multiple platforms (such as Twitch, YouTube, Facebook) at the same time. Very helpful plugin for anyone streaming on Linux!
Hope to see this one among the OBS plugins on flathub soon. Thank you very much if you consider it! 
Name: OBS-multi-rtmp Multiple RTMP outputs plugin | OBS Forums
Homepage: GitHub - sorayuki/obs-multi-rtmp: OBS瑜囨暟銈点偆銉堝悓鏅傞厤淇°儣銉┿偘銈ゃ兂
License: Create LICENSE
Developer has been contacted: Yes Multistreaming on Flathub? 路 Issue #445 路 sorayuki/obs-multi-rtmp 路 GitHub