this repo is the official repo of ISPConfig
and this repo is from my company
I think we are one of the first whoever used the ispconfig package system publicly and as a lot of people had issues installing our plugins to there roundcube system, we provided a package what does everything for the user. This package still has an older version of the roundcube and the plugins itself, but will be updated in the next couple of weeks, as next week the new versions of the plugins will be published per svn, git and per zip file.
PS: What do you mean by managing roundcube in ispconfig?