Ubuntu 15.04: Screensavers for MATE

Install some gnome screensavers:

apt-get install xscreensaver-data-extra xscreensaver-gl-extra

Go to screensaver folder:

cd /usr/share/applications/screensavers

Edit the .desktop files, changing OnlyShowIn=GNOME; to OnlyShowIn=GNOME;MATE; suchlikewise:

sudo su
find . -name '*.desktop' | xargs sed -i 's/OnlyShowIn=GNOME;/OnlyShowIn=GNOME;MATE;/'
exit

The screensavers are accessable in System->Preferences->Look and Feel->Screensavers