reflog is this superhero that only appears when it has to save your ass.
A neat thing about it is that it logs everything you do in a given machine. It works locally, none of the reflog is pushed anywhere, and if you 'git clone', your reflog is empty. But...
For us, that are work are doing very far from BlueGreenDeployments, by doing git pull in a server and reloading (in Common Lisp planet you do hot reloads like a boss), this gives a track of when did pulls happen, and so you can find re-imagine the history of deploys, pulls, deploys, fixes.
It's a suboptimal solution, but given it's for free "don't look a gift horse in the mouth".
As usual in the class of git commands that list info, there are lots of formats and customizations. For me, a simple "git reflog --pretty=oneline --date=short" does the job.