Related to T118062.
In simple.wikipedia.org and sco.wikipedia.org:
Create a citation with {{efn-ua}} suchas {{efn-ua|Message}} and reference in the notes with {{notelist-ua}}
The notelist will be correct using the letter A but for simple.wikipedia.org and sco.wikipedia.org the reference in the body will say [upper-alpha 1] instead of [A]
This syntax works correctly in en.wikipedia.org. In the English wikipedia where the notelist has A and the citation shows [A]
Example pages include
https://simple.wikipedia.org/wiki/International_auxiliary_language
https://sco.wikipedia.org/wiki/Seleucus_I_Nicator
I've duplicated this on Windows 10 using Edge, Firefox, Chrome and Opera. I've also duplicated it on my iPhone SE iOS 14.4 in Safari