How does [Desktop Action ...] work?

[Ernst Persson]

Is there a real specification for [Desktop Action ...] yet?
A list of standard actions would be great!
Does the freedesktop tools support this, so the information
can be collected from all desktop-files to a database?
This would be great for gnome-volume-manager and
gnome-default-applications for example, which both let's you
choose an application for a specific action.

[Desktop Action PlayCD]
Name=Totem
Exec=totem --play --dev=%d
OnlyShowIn=GNOME

Like this?

Regards
/Ernst Persson