Well thank you for that information!
I always wondered why the Tenderflake lard recipe for pastry had a cup of cold water, a beaten egg, and a tablespoon of white vinegar. That explains it!
I’ve read about vinegar in pastry too, long ago enough that I don’t remember but I think it’s different purposes than with the cake ....but King Arthur knows:
“What does that vinegar do? The most common answer — that it affects gluten development — isn’t actually that useful. If you had a mass spectrometer at home, you could measure the teensy difference vinegar makes in the tensile strength of gluten strands in the dough, which in theory makes it a bit more tender.
But there are two much more important perks to using vinegar: it provides a little insurance against overworking the dough. And, that splash of vinegar will keep your dough from oxidizing and turning gray.”
https://www.kingarthurbaking.com/blog/2018/08/15/vinegar-in-pie-dough