I am running 15.10 and so far it is running well!
However there are some bugs in VLC 2.2.1 and I want to either downgrade or get latest version.
I have played around with VLC daily build PPA on virtualbox (just to test before doing this on my main pc).
However if I wanted to downgrade from VLC 3 git back to the stock version I have to remove VLC and then reinstall it from ubuntu PPA but if I try to uninstall vlc it also wants to uninstall ubuntu-mate-desktop.
I have tested it in virtualbox and removing ubuntu-mate-desktop doesn’t seem to have any side effect but I just want to know what is that package before doing this on my main PC.
Also just wondering what happened to Ubuntu Software Centre? It doesn’t appear on clean install of 15.10.
ubuntu-mate-desktop is a meta package. It's like a list of what other packages that it will install, in this case, it's just the packages that come pre-installed.
Removing this will not have any effects, they say it could affect upgrades, but I didn't have this meta package installed while upgrading 15.04 → 15.10. If you was to install it later, then VLC would want to install the version that ubuntu-mate-desktop (pre-installed) states.
It's been removed by default in 15.10, replaced by ubuntu-mate-welcome to install a handy choice of apps or install other software managers that are not as resource hungry or slow as Ubuntu Software Centre.
Ah that explains why Ubuntu Software Centre is on my main pc (which has been upgraded from 15.04 to 15.10) but not on clean install of 15.10 in Virtualbox.