Permanent Mute is a free Chrome extension developed by edwardr. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools.

This extension is designed to tackle the problem of annoying and ill-timed sounds on websites. It effectively stops auto-playing video sound and ensures that the websites stay muted until you choose to un-mute them. Even if you close the website and revisit it later, the mute setting remains in place.

While it is worth noting that a similar feature is expected to be introduced in Chrome 64, Permanent Mute provides a solution in the meantime. With this extension, users can have a more pleasant browsing experience by avoiding sudden interruptions caused by unwanted sounds on websites.