If memory serves, adobe announced the end of support for Type 1 fonts just last year. (This was mentioned in a conference talk, but apparently it's official: https://creativepro.com/adobe-is-ending-support-for-type-1-f...)

In any case I've coincidentally spent the week spelunking in the truetype spec; there are tons of old representations and font features that a robust font parser is still expected to support, and some of it is wonderfully arcane.