This is inspired by this question, where an alternate character of a font is only available via OpenType’s access all alternates (aalt) feature. My question is simply: Is it possible to access this feature in some way or even as intended with XeLaTeX?
Fontspec, which should be the obvious choice for this, does not mention this feature in its manual. This answer does not do this for reasons explained in a comment.

RawFeature=+aalt– egreg Jul 14 '15 at 09:58aaltwill also use small caps. – egreg Jul 14 '15 at 10:08RawFeature=+aaltseems to acivate all the first alternatives fromaalt(which probably are the respective small caps in some fonts, but not always). So it gives you access to some of the characters, but not all and not on a per-character basis. – Wrzlprmft Jul 14 '15 at 10:30