Last modified: 2014-07-25 01:07:21 UTC
We could use window.onerror to log occurrences of JavaScript errors (possibly sampled).
Turning this into a bug for MediaWiki core.
Gergő Tisza (Tgr) also started an RFC at https://www.mediawiki.org/wiki/Requests_for_comment/Server-side_Javascript_error_logging in case anyone missed the URL field change.