It was both. There were two separate software based on the same underlying technology:

* ToroDB Stampede[1]: MongoDB replica, converting on-the-fly documents to relational structures. Targeting OLAP, as data normalization made queries from some % faster to 2-3 orders of magnitude faster.

* ToroDB Server[2]: what DocumentDB is or FerretDB is planning to be. It was less developed than Stampede, certainly.

[1]: https://github.com/torodb/stampede/

[2]: https://github.com/torodb/server

(edit: formatting)