Repro build folks are introducing variation in the build environment (inc with disorderfs) in order to uncover reproducibility bugs and then fix them. Here are the variations Debian is introducing:

https://tests.reproducible-builds.org/debian/index_variation...

It is similar to how Chaos Monkey increases the resilience of Netflix's service by introducing random failures and then for each of those failures working out how to prevent the failure from affecting the overall status of the service.