Just wanted to hello all and big thanks to Urbackup devs and contributors. I had heard about UrBackup a long time ago but never got around to trying until Crashplan stopped letting me use their software to backup my local pcs.
I never used their paid service but I did use the software to backup between pcs, but I guess keeping track of encryption keys and accounts was too burdensome for Code42.
I also lost access to my old backups from them as I didn’t manage to find out how to restore Crashplan backups until much after they closed down and I had no backup of my keystore db. (Plan C Crashplan, https://github.com/OurDataNotYours/PlanC )
Anyways, I have an interesting idea regarding exclusion lists that I will post on the Feature request forum but the basic idea is there are already many programs that clean out temp directories and misc useless files. An example of this is CCleaner. There is also another program, CCleaner Enhancer (CCEnhancer) which adds a ton more “temp file location” resources for cleaning. I think it might be worth considering importing these locations as exclusions for UrBackup resources. These exclusions are already maintained by a community, and as far as I can understand it, the files these programs (CCleaner etc) would delete, are EXACTLY the same files we should not back up. 
Might be a good idea!