At the moment, Special:CentralNotice only allows a manual selection of languages or wikis.
A nice addition would be to have a way to import a list of languages, defined in a certain format.
There is an example with T220080. This task is about creating a banner that would be displayed on 889 wikis. A list of languages and wikis is provided, and have a simpler way to import them to the CentralNotice system would be great.