"After sifting through TikTok's code, this is what Bangorlol found:
Phone hardware (cpu type, number of course, hardware ids, screen dimensions, dpi, memory usage, disk space, etc)
Other apps you have installed (I've even seen some I've deleted show up in their analytics payload - maybe using as cached value?)
Everything network-related (ip, local ip, router mac, your mac, wifi access point name)
Whether or not you're rooted/jailbroken
Some variants of the app had GPS pinging enabled at the time, roughly once every 30 seconds - this is enabled by default if you ever location-tag a post IIRC
They set up a local proxy server on your device for "transcoding media", but that can be abused very easily as it has zero authentication"