"Plasma 5 looks pretty cool. Does Triskel 7 come with it? Or will Triskel 7
auto-update to it?"
As Magic Banana said, Plasma 5 won't be in the 7.0 repos because 7.0 is based
on Ubuntu 14.04. Ubuntu will include Plasma 5 in 14.10, so Trisquel 8.0 will
include it. That will be in about 2 years from now, based on Ubuntu 16.04.
You can follow the instructions here to add the PPA. Those are bleeding edge
builds, though.
"What's the key combination for this search feature? Does it work like
Synapse?"
In Plasma 4, the key combination for KRunner is Alt+F2. It's probably the
same in Plasma 5.
