SQL is a nice formal definition for these metrics. Even though it may become out of date (the prod database doesn't change in backwards incompatible ways that often), it's still a big win for the metrics pages IMO.

I agree. It'll be out of date, but so is the SQL we pasted into the top of each wikimetrics metric [1]. These kinds of things are useful and hopefully get updated as query strategies improve (eg. better data warehouse schema)

[1] https://github.com/wikimedia/analytics-wikimetrics/blob/master/wikimetrics/metrics/rolling_active_editor.py#L17