Since I’m working with a very large amount of .locl glyphs that I often add and subtract from, I have to manually copy and paste the substitutions from the locl table to the stylistic set feature.
Is there any to have the stylistic set be kept in sync with a certain language’s locl substitutions through either opentype or or a script?
The locl feature defines lookups. You can reference those lookups in the stylistic set features.
So if you have this in locl:
lookup locl_latn_0 {
script latn;
language AZE;
sub i by idotaccent;
language CRT;
sub i by idotaccent;
language KAZ;
sub i by idotaccent;
language TAT;
sub i by idotaccent;
language TRK;
sub i by idotaccent;
} locl_latn_0;