The multiversion setup directory has grown into a more general purpose "set up my dev environment" script that we'll likely move out of the Server repo so it can be more easily used by downstream teams.

In the short term, we can start making the new functionality more obvious by adding a README with example use cases for the following.

1. Reproducing a multiversion test failure
2. Setting up the dev environment for a particular Evergreen patch version for use outside of the main server repo (e.g rep repo: mongocopy) (mainline versions are technically supported as well, but I think it's a less common use case and there not be binaries available)
3. Top-level APIs for integration into other scripts (e.g. symbolization or task generation). This can be moved to a separate CONTRIBUTING file later on when we move the code out of mongodb/mongo