It's not easy yes. But it's not pressing i think. 
The most important is to check the core.

After all, for the extension we have to cases:
 - the extension use only a subset of the core events
 - the extension add his own events

For the first case, maybe can we check only if the event match with the one registered in `phpBB/docs/events.md`.
And for the second case check the new events with an events.md file located in `ext/vendor/extension/docs`.
But it's require more work and a more complicated exporter.