The ATProto underlying BlueSky social network is similar. It uses a content-addressed DAG.

Each “post” has a CID, which is a cryptographic hash of the data. To “prove” ownership of the post, there’s a witness hash that is sent that can be proved all the way up the tree to the repo root hash, which is signed with the root key.

Neat way of having data say “here’s the data, and if you care to verify it, here’s an MST”.