It's not missing, nor are the yaml files. In particular, the PM rebuilder was never, ever on the website.
All you need do is just what you've always been able to do. Put in a ticket and ask. Ask, and you shall receive.
The PM rebuilder was never on the website to my knowledge. The downloads page is still there (
http://www.ubbcentral.com/downloads), though very very out of date. Still in the same place as always. The rebuilder is not listed. Has never been. I seem to recall there being some issues with it therefor Charles never wanted to make it widely available. I quite honestly do not remember what the issues were. I haven't messed with some of this stuff in 2 or more years now. Make a complete backup before you run it is all I can tell you. Put in a ticket and we'll get you a copy.