Writing a Chrome Extension (devtools, action or `document` types, and payment collection)

Okay, let's write a Chrome extension. I've done this before, but couldn't really remember how, and since "manifest version 3" for Chrome extensions is some sort of big deal that changes all the rules, I might as well start over. Google does have a "Hello World" tutorial here , but it's important to note that the "Hello, World" extension is what at least this answer at SO calls a popup extension .…