According to https://unix.stackexchange.com/help/on-topic:-
Note that Ubuntu posts are a special case. If your question applies to Ubuntu only, or you're looking for answers that are Ubuntu-specific, you should post it on the Ask Ubuntu Stack Exchange site.
Also ubuntu says:-
Note that http://askubuntu.com is specifically dedicated to Ubuntu questions.
Sometimes Users ask question which are Ubuntu specific. When I flagged questions like this as Off-Topic > Migration I found meta.unix.stackexchange.com and stackoverflow.com But askubuntu.com is missing.
There are many chance may Ubuntu specific questions are posted here (as well as programming question -stackoverflow) instead.
So, I think one more option should be provided:- belongs on askubuntu.com.