Substack

 Substack does not seem to be searchable by individual posts by any given author. 1/15/2022

Apparently the reader would have to go through every single post looking for whatever reference.

That seems like a BIG oversight in services to me.

So, I am using the free version of Substack as an email client linking back here. Perhaps there's a clue to be explored. Perhaps PAID versions allow for hat feature.