Currently there are several usages of the interwiki prefix cmn: https://global-search.toolforge.org/?q=%22[[cmn%3A%22 Example in enwiki: https://en.wikipedia.org/w/index.php?search=insource%3A%2F%5C%5B%5C%5Bcmn%3A%2F&title=Special%3ASearch

This prevents changing the prefix cmn from an interwiki prefix to an interlanguage prefix by T230226.

Please replace [[cmn: by [[:cmn: in the wikitext of all Wikipedias.