Changes take effect at once and are remembered. If you edit one of the included schemes, a copy of your own is created automatically, marked “(custom)”.

A redacted page becomes an image — that is the only way the text underneath is really gone. Every piece of text outside the bars then comes back as an invisible layer, so the page stays searchable. The browser fetches the language files for text recognition from the net on the first run (about 10 MB each).

The settings live in this browser’s storage. They do not come along when you move to another device or browser — that is what the backup file is for. The PDFs you have open are not part of it; they never leave your machine.