What's the patent status? As far as I know, H265 is patent encumbered(and not actually supported on a large chunk of Android devices for the same reason) , so including this somewhere might invite legal trouble.
I was under the impression most implementations rely on hardware support. Hardware vendors pay the royalties then software just hands it off. Afaik that's how it works in most browsers and many modern CPU/GPUs support hardware decoding h265
