I am very new to linux and all the open source stuff (my first post on lemmy actually) so I don't get how this stuff works but flathub is saying that floorp is proprietary. But after a quick google search it says that floorp is open source licensed under MPL 2.0
The contribution is automatically relicensed under that licence and as such, it remains property of the org that made floorp, so they're technically getting free labour, support and maintenance