Not sure if we can even manage this. But it would be nice when you could cycle through the three buttons in the unsaved changes dialog. So that you don't need the mouse to reach the discard changes button. This is very common in quite a few software ...

Investigating the possibilities ...
This part is done in pure C. No access by python. And Blender does not support such tabbing from what i know.
Well, was a nice dream. Closing.
kthotheoz wants to have a look at it. Maybe he finds a way.
Dialog is in source\blender\windowmanager\intern\wm_files.c
I think it is safe to close this issue. We haven't touched it since over a year, and will most likely never touch it.
Closing.
@iyadahmed, do you see a chance here? If not, no problem. Then we will close this issue again :)
I'll give it a try :)
just curious, would this be done through arrow keys, scroll wheel or so?, I think it is already done by OS using tab key
Arrow keys usually. Left and right. That's how it works in Gimp for example. Tab key does not work here.
oh ok, will give it a try after other task
No pressure :)