Try to see if system fonts can be found in the active bundles

[pkgw]

Maybe a document specfies a font that is resolvable as a system font, but it turns out to be the same thing as a font that we have in a bundle. In that case we should figure this out, use the bundle file, and suggest to the user that they specify the font in a way that results in it getting pulled from the bundle rather than having to go through the system file lookup. (In particular, you need to specify the font as a particular file name: texgyrepagella-regular.otf, not TeX Gyre Pagella.)

[khaledhosny]

You can add the fonts in the bundle to FontConfig configuration using FcConfigAppFontAddFile or FcConfigAppFontAddDir, then asking for these font by font name (i.e. TeX Gyre Pagella) should work.

[auscompgeek]

Specifying \set*font by filename would break bold/italics. Is it possible to look up font bundles by font name?

[pkgw]

@auscompgeek It doesn't need to break bold/italics, if I'm understanding you properly ... see the recipe given here.