When your edit trips the blacklist or an editfilter, you get a very technical and uninformative message.
The edit filter causes: "Error: The notification you tried to make was aborted by an extension hook" to show in the 'save' dialog.
The URL blacklist: "Invalid code error" apparently.
Since this is quite common for newbs to trip, it should be handled better.
Version: unspecified
Severity: critical
URL: https://en.wikipedia.org/w/index.php?title=Wikipedia:VisualEditor/Feedback&oldid=562806113#Blocked_sites