• Also, mention TIMING=1 env var to for breakdown by rules to help figuring out if this is even the relevant repo?
  From googling up as a newcomer (and I'll admit I haven't read most of the docs yet), I'm now bouncing between typescript-eslint <-> plugin-import, both of which IIUC tend to parse the whole transitive closure of imported files(?). The https://typescript-eslint.io/troubleshooting/performance-troubleshooting/#eslint-plugin-import section was useful 👍 but could be great to include some advice / recommended DEBUG= values to confirm how much double/transitive parsing is happening.

TIMING=1 isn't great as it's misleading for cross-file rules.

It doesn't take into account caching that's done. For example type information is calculated lazily and cached - so the first type-aware rule that runs will "do more work" than other type-aware rules. This can cause TIMINGS to report that rule with a large runtime - yet if you were to remove that rule you'd just find another rule will see its reported time grow massively.

It also doesn't take into account time spent in selectors - meaning rules can hide their runtime by converting logic to a selector query (even though the impact is the same).

Finally it also doesn't take into account time spent in a rule's create function - which can hide a lot of weight.

In general I wouldn't trust it much more than a wet finger in the air estimation at best.