Using a folder you already have

This is the point of the feature.

Open Settings → Notes → Notes folder, or press 3 and choose "Use a folder I have", and pick any folder of markdown. Everything in it is listed as a note straight away.

If another app changes a note while you have it open here, TypeFire notices and asks which version to keep rather than overwriting yours or theirs.

The browser's permission for the folder

Picking the folder is the browser's own dialog, and so is the permission to keep reading it. Chrome asks in two ways: Allow this time lasts only while a TypeFire tab is open, so closing the last one and coming back finds the folder locked again; Allow on every visit keeps it open from then on, and is the one to choose. When the folder is locked, the Notes pane says so: click anywhere and Chrome asks again. A capture made from the Spotlight while the folder is locked is kept and written the moment the folder is open.