Can I get a quick overview of GtkApplication actions?

[Sandy Armstrong <sanfordarmstrong gmail com>]

Howdy,

I wasn't sure what list to email, so apologies if this is the wrong
place to ask.

I've heard some rumblings about the new GtkApplication having the
ability to export "actions" in such a way that other apps can easily
find and invoke those actions.  But the docs in GApplication and
GtkApplication seem a bit short on details.

Can anybody explain to me (or link me to an explanation) of what this
feature is and how it works, and how it's expected to be used in (for
example) gnome-shell?  Are the actions discoverable even when the app
is not running?

This could tie really nicely into some work I'd like to do to bring
Windows 7 Jumplist-like functionality to GNOME, but I want to make
sure I understand exactly what's currently implemented or planned to
be implemented.

Thanks for your time,
Sandy