When I click the ULS on the desktop, I sometimes see "شامي" ("Shami", Levantive Arabic, `apc`) as one of the languages listed in the "Missing in ..." line, which is added by CX, and in the little "Translate this page" panel.
I connect from Israel. According to CLDR, and consequently, ULS/language-data, Levantine Arabic is one of the languages spoken in Israel. It's correct in real life, too, but technically, it's incorrect for CX: there is no Wikipedia in this language, so showing it in this context is useless and misleading.
`apc` is just an example. CX must only suggest translations into languages in which there is a Wikipedia, and which are fully supported by CX.
(I actually believe that showing not-yet-fully-supported languages in ULS is a very good idea for the future, but it's too early for it with the current infrastructure.)