In TIG-3147, we introduced two new diff testing modes for the change stream fuzzer,  "serverless" and "serverlessNoOptimization", and we created the appropriate jstestfuzz self-tests. However, as far as I can tell, we never created evergreen tasks for these modes, so they are not running on the waterfall or generating BFs. Maybe this was on purpose; filing this ticket so we can investigate.

 
Here is the only change stream fuzzer task definition I can see, and it's for the optimization diff testing mode.