Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
They have a lot in common, indeed they are about the exact same website:
Following common sense, we should merge them or make a synonym or other things we commonly do in such cases.
mediawiki-commons at this time it has 0 (zero) questions, actually it is not listed on https://webapps.stackexchange.com/tags so just ignore it.
wikimedia-commons has 4 questions.
ale recently posted Please rename [commons] to [wikimedia-commons]