Version:           3.0 Beta 2 (Battleship) (using 4.1.1 (KDE 4.1.1), Kubuntu packages)
Compiler:          cc
OS:                Linux (i686) release 2.6.26-5-generic

As originally reported here: https://launchpad.net/bugs/41644 it seems that the enter key could be used to improve Adept's keyboard navigability, thus increasing accessibility.

Shameless copy/paste of the bug: 
"This is a wishlist item. It will marginally enhance accessibility by keyboard but especially improve the convenience of the UI. When the focus is on the package list, Enter/Return does nothing until the listed package is expanded (right cursor), and the tab focus is brought around to one of the buttons ("install/remove" and "details").

 The following improvement would be similar to the expand/collapse feature of the left and right cursor actions on the focal list item: Enter/Return could be made to cycle through the different available actions, namely "install", "upgrade", "remove" and "purge" (also "cancel changes"). This improvement would mean the mouse does not have to be used, and neither do the left and right cursor keys (plus several tab key-presses), to choose the desired action.

 This would be very useful to those who know what a package does, and for example merely want to upgrade or remove a package with a minimum of graphical changes, and fewer key strokes. It would cover those users who are not necessarily new to Kubuntu but prefer Adept to apt-get's command line interface and Aptitude. And it would include those with slower computers who prefer a GUI over the shell.

 For multiple selections with different available actions, the Enter/Return key probably ought not to toggle arbitrarily through different available actions, so the Enter/Return action might default to no action, or simply bring up the context menu."