At the moment, installing these is a manual process involving a secret ritual conducted somewhere deep in the bowels of the Stack Exchange offices, involving unicorns and ... oh wait, I'm not supposed to tell you that part.
Anyway, yes, we can get these added. One merely needs to propose specific text to go into the popup and the tag to which it should be attached. SE won't approve generic messages. Instead they should give specific guidance for asking good questions related to that specific tag. The example shown above in the question is a good example.
The proposed text can contain links, e.g. to meta posts, if necessary.
Open a new meta question under the tag tag-warnings with the proposed text and the tag to which it should be applied. This will allow for community input to improve the text, if necessary, before we kick it upstairs.