After circling it for a while, rather like a ship around a whirlpool, I've fallen down the rabbit hole of Obsidian plugin.
Although making any contributions to a closed-source project is kind of distateful to me on principle, I admit that after a bit of perusing the API's seem pretty robust.
My goal is to create a plugin which can help track the creation of paragraphs-- actually groups of paragraphs. Turns out there's not a good word for a "group of paragraphs", other than "section" which is so agonizingly generic. So I made up a word, a "themagraph". It's a group of paragraphs which share a common theme or subject.
The extension will track when a themagraph is started and when it is created, as well as when it is last edited. They'll also be able to store arbitrary metadata about that themagraph.
Why do this? I've found that it's vastly easier to dump all my thoughts into one file and sort out which paragraph (or group of paragraphs) pertained to what topic later on. This " themagraph" is the ideal unit for me to associate with a given subject.