Kiln checkins:
See this post on the Kiln Knowledge Exchange
Other source control systems:
Here's the regex from the code:
re.Pattern = "\s*BUG[ZS]*\s*IDs*\s*[#:; ]+((\d+[ ,:;#]*)+)"
This would lead me to believe that
bugzid
bugsid
bugz id
bugs id
will all work, and it's pretty lenient about the colon, too.