It originated (more than 20 years ago) as a fork of SWReality, which is itself a fork of SMAUG, which comes from DIKU, and so on and so on.

We (myself and a lot of other awesome volunteer coders over the years) have made some pretty major modifications to the codebase. It all runs on PostgreSQL now (instead of flat text files with a custom parser), it has a built-in Lua scripting interpreter for extensions and in-game interactions, it has deep integrations to our Discord community, it has sidecar web services, and much much more...