This extension displays an icon in your address bar if it detects RSS, Atom, or JSON Web Feeds on the active website. Click on it to open a Popup showing the feed URLs and a Button to copy the corresponding URL to your clipboard with one click. Complete Installation: After adding the extension to Firefox, grant it permission by navigating to about:addons in Firefox, then > WebFeed-Indicator > Permissions, and enable "Access your data for all websites". See below why this permission is required. After that, try out the extension by navigating to https://blog.mozilla.org. The icon should appear in your address bar. Click on it to reveal the available feeds. Click on one of the copy buttons to the left to copy a feed URL to your clipboard. You can paste the URL into your favorite feed aggregator software to subscribe to it. Compared to other feed extensions, this one puts an emphasis on a limited feature set and quality. Features:

Good theme integration
Open Source
Works completely on your local computer
Simple, limited feature creep

Permissions: To extract the feed URLs websites advertise from their HTML head tag, this extension unfortunately requires being able to read the content of the websites you visit. Feel free to verify in the source code that this power is only used for a simple local HTML query.