O/T : linux: can I list which small caps are in a ttf/otf font ?

[Karl Berry]

    https://github.com/adobe-type-tools/agl-aglfn/blob/master/glyphlist.txt

BTW, it's also in TL at texmf-dist/fonts/map/glyphlist/glyphlist.txt.
(An older file with a different license, but the same glyph list.)

For completeness, you may also want to consider
texmf-dist/fonts/map/glyphlist/texglyphlist.txt
although I don't see anything related to small caps there. --best, karl.