Kudos to k0s and sinemetu1, the current maintainers of mozregression, an idiot-proof script for helping you find the regression range for a bug. Give it two dates, and it automatically downloads and runs a nightly and, when you exit, asks you whether the bug is present or not and downloads another build accordingly, until you have a 24 hour window identified. And then it says “do you want to compile some code to narrow it down even more?”. Awesome.