Which commit is live, and when did it start?

This exists because "I pushed a fix and I am not seeing it" had no answer short of reading a dashboard: nothing the running process served said what code it was. A deploy that never happened, a deploy that failed back to the previous image, and a real bug in the new code all present identically — as the old behaviour — and the only way to tell them apart was to guess.

Deliberately unauthenticated and deliberately thin: a commit SHA and a start time, which is what a health check and an operator both need. Nothing about accounts, data, configuration or the environment goes here.