It’s a joint venture between ARM, Gemalto and a few other companies iirc.
*Trusted Execution Environment
AMD hasn't really had any hardware for the enterprise for a long time so they are quite behind on many things.
This is their free remote admin tool : https://community.amd.com/community/devgurus/dmtf-dash/blog/...
It can basically do quite a few things, change firmware, boot an image, redirect USB input and likely quite a few of other undocumented things.
With Ryzen Pro launching soon I guess AMD would release a new suite of remote management software.