Creating incremental MAR files should not include Tor Browser version in meta data
While trying to build the incrementals for 5.5.2 on a machine that had older mar-tools I ended up with them not matching incrementals built on other machines. Upon investigation it turned out that the browser versions gets embedded in the MAR files' metadata. There is no need for doing that actually.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information