Private TM Data Handling in Self-Hosted MateCat Server

[groundcat]

I installed a MateCat instance on my own Ubuntu server and have a question about the translation memory (private TM). When I upload my private TM to the server, it provides me with a key.

Does this key indicate that the TM is stored on my on-premise server and only accessible on this self-hosted server, or is it uploaded to a remote service hosted by MateCat, with the key provided by MateCat to access my private TM?

For some compliance reasons, I would like to know in the self-hosting scenario how my uploaded private TM data is managed or uploaded and whether it is shared with MateCat or Translated.

I understand that the MateCat-hosted server at https://www.matecat.com uses the uploaded TM in some way (public MyMemory), but I'm wondering if the same applies to the self-hosted on-premise version with private TM.

Thank you.