I have various keyword searches set up (such as "b" for bugzilla) from the url bar. They seem to have stopped working in build 20180217220052.

Actually, all my one-letter searches disappeared. I had both "b" and "bug" set as keywords for a bugzilla search from the urlbar. "bug" still works. I also had "w" for wikipedia, which is now not working.

Unfortunately we had to remove duplicate keywords, because our UI doesn't admit those and due to a bug they were "working". And sadly there was no way to save them (Apart from changing them to something that the user doesn't know about). 1 url can have multiple keywords only if they differ by POST data.

now that I think about that, we may want a relnote. I'll add that request there.