Last modified: 2012-08-01 21:10:18 UTC
When using the Interwiki extension, you can put all sorts of garbage into the "prefix" field (such as "<>[]|") and it'll be gladly accepted and stored. The input should probably be validated for legal title characters, at a minimum. Interwiki prefixen may have stricter rules (bound to ASCII?). That'll require some research.
reducing priority since my initial priority was wrong.
Apparently Amir submitted https://gerrit.wikimedia.org/r/#/c/17223/ which Siebrand merged. Marking as FIXED.