@timotheus Releases are based on Ubuntu, you can see the specific bases at https://en.wikipedia.org/wiki/Elementary_OS#Summary_table
I believe it can use Ubuntu packages, but it is has it's own "app store", but whatevs, just use apt. ^_^
So, when you hit cmd + tab, this pops up. I can keep hitting that key combo and selector will "walk" through options. pretty standard.
but, i can also use arrow keys when this is up, or use pointer to select app I want.
basically, i almost always overshoot the app i want when using this key combo, and being able to go back one (via right arrow) vs having to "walk" through the entire list is the killer feature for me. Seriously, not having it caused me frustration 20x a workday.