WMF currently only publishes a list of available fonts on meta:SVG fonts (and https://noc.wikimedia.org/conf/fc-list), without any mention of the order of font selection for generic families sans-serif ("Sans") and serif ("Serif"). Since those two generic families, sans especially, are in fact the most commonly used by default, WMF should publish the said lists. They can be generated by running fc-match -a Sans and fc-match -a Serif respectively.
The order problem is especially a problem with CJK languages, as many distributions and even fontconfig's own nonlatin file mixes up sans ("Gothic", "Hei"), serif ("Ming"/"Mincho", "Song"/"Sung"), and script/cursive ("Kai") families. So please publish results for stuff like fc-match -a Sans:lang=zh-cn too.