Where can we put feature request? Wouldn’t it be good to have a category for that?
I’m sorting photos giving grades 0 - 5 but can’t use NumPad for this (at least in Windows version 2.4.1). It would be a nice feature as you can do it one hand - thumb on cursor to change photos and three fingers on NumPad. Left hand can hold a glass of wine 
Rating the photos works only with the regular number keys, not with the keys on the numpad.
As far as i know, redmine is for both bug reports and feature requests: https://redmine.darktable.org/projects/darktable
Generally the numpad can either send the same command as the numbers on the main part of the keyboard or send their own unique numpad code. You should check which code your numpad sends.
You can also set custom hotkeys for this in the settings.
I thought I couldn’t change the shortcuts as my first try failed, but I figured it out:
The rating can either be done in the lighttable or in darkrooms filmstrim. Thus the shortcuts need to be changed for both. (At least I’d like to have them both on the numpad). They are found under settings->shortcuts->modules->filmstrip and settings->shortcuts->views->lighttable.
I just typed the numbers with the numpad and afterwards the rating works via the numpad.
EDIT: My excitement was premature. It does not work for both. Only one of them can be set to the numpad. If one is set, the other rating shortcuts just get deleted and don’t work at all, neither with the regular number keys nor with the numpad.
@matejmarti Looks like the two key sets aren’t interchangeable, at least with dt in win.
This might be relevant. I haven’t tried it myself though.
My problems are with darktable in linux. 
Okay, makes more sense because they are different keys. I wonder if the feature request would be to be able to assign multiple keys combinations to a single binding. I never rate images so this doesn’t concern me. Just a suggestion.