The extension is in both stores
Chrome and Firefox both publish it now, at 2.2.0 and from the same source tree. The page you are looking at becomes Markdown from the button in the toolbar, a side panel follows you from tab to tab, and the fifteen conversions this site has run inside the extension, on your own machine. Signed out it never talks to us at all.
Two stores, one extension, and the same build in both.
Where it is
Chrome takes it from the Chrome Web Store, and so do the browsers built on Chromium: Edge, Brave, Opera, Arc. Firefox takes it from Mozilla Add-ons, on the desktop and on Android. Both stores are at 2.2.0, which is the version this repository is at — the same source tree built twice, with three manifest keys and one file between the two.
What it does
Press the button in the toolbar and the page you are looking at comes back as Markdown: the article picked out of the navigation and the cookie notices, every link and picture address made absolute. Copy it, download it, or save the page as a self-contained .html file, its own design and its pictures inside it.
The side panel is the same thing kept open beside the page, following you from tab to tab and converting each page as you arrive. The right-click menu converts a selection. And the fifteen conversions this site has run inside the extension too, so a file on your machine converts without being uploaded.
The pages this is for are the ones with no export: a wiki, a ticket, a thread, documentation — anything that exists only rendered. It reads what your browser already has on screen, so a page only you can see converts without anybody handing over a password.
What it asks for
No host permission at install. Signed out it never talks to us at all — the conversion happens in the page, on your own machine — and there is no analytics in it and no record anywhere of which pages you converted. Permission to read the tab you are on is asked for when you turn Chrome's side panel on, and refusing it costs the panel and nothing else; in Firefox the sidebar is a manifest key and asks for nothing.
Signed in, an OAuth token sits in the browser's extension storage — the same grant listed on your account page and revocable there. Save puts a document where the rest of them are, and Share publishes a link or names the people who may read it.