Certain API modules use a list of sites (enwiki, dewikisource, frwikiquote and so on), for example https://www.wikidata.org/wiki/Special:ApiSandbox#action=wbgetentities and a lot more. The order in these lists is currently pretty much random: Currently it starts with a wild mixture of Wikibooks, Wikisource and other projects and ends with an almost, but not perfectly alphabetically sorted list of Wikipedia languages.
Patches for review: