We’re talking about Android, unrar doesn’t have anything to do with this really.
The entire topic is about RAR archive support on Android, so of course the freely available source code of unrar, released by the RAR developer himself, has absolutely to do with everything here.
RAR is and will continue to be a proprietary format with an owner who can seek royalties.
Nope, unrar’s source code is free, released by RAR’s developer.
It’s like saying Google should stop licensing MPEG because ffmpeg exists—it simply doesn’t work like that
Nope, it absolutely isn’t like that. You just have no clue at all.
<span style="color:#323232;"> Unrar source may be used in any software to handle RAR archives
</span><span style="color:#323232;"> without limitations free of charge, but cannot be used to re-create
</span><span style="color:#323232;"> the RAR compression algorithm, which is proprietary. Distribution
</span><span style="color:#323232;"> of modified Unrar source in separate form or as a part of other
</span><span style="color:#323232;"> software is permitted, provided that it is clearly stated in
</span><span style="color:#323232;"> the documentation and source comments that the code may not be used
</span><span style="color:#323232;"> to develop a RAR (WinRAR) compatible archiver.
</span>
It’s not FOSS, given that it comes with the provision that no RAR compressor can be created based on unrar source code but for browsing and extracting RAR archives, the unrar source code as is is absolutely fine.