Not sure what it is. I usually pinch off such stuff and put it in the burn pile, hoping that will prevent it spreading.
Garden’s alive Catalog has pictures of various diseases and advice on treatment, so when I want more info, I usually start there.
When I had a problem with something last year, I took an affected leaf, put it in a ziplok bags and went to the Mrs Henderson at the seed store. She pulled out a book that looked 50 yo, and went to the peppers and started looking at the pictures to ID my problem. Now that is customer service in the old way!