Lots of cheap Android smartphones do, why wouldn't TikTok? I just don't think they get anything material out of the integration due to the unbelievably low signal to noise ratio.
I’d venture to say it’s filtered to knowing who influences culture. Then pinpointing what those accounts respond to. Then designing content to shift said culture through this channel.
Who knows. People being people, the backdoors that are likely there might be easily visible from the source code. And they may be identical to backdoors used elsewhere. Devs do not like to reinvent the wheel.
And scrubbing them out without trace prior to ownership transfer is not easy. One forgotten backup copy of the Git database is enough to leak the info.
Yes? It's neither technically impossible nor beyond a totalitarian state to do so. So why would you presume otherwise?