HerpDerpTube is a free Chrome extension developed by Dan Orzechowski. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This extension aims to replace YouTube comment text with the phrase "herp derp" as a way to preserve sanity.

With HerpDerpTube installed, users can click on each comment to restore its original text. This feature allows users to selectively view the original comments if desired.

Please note that there is another similar extension available that works on more browsers, and it is recommended to use that one instead.

Overall, HerpDerpTube provides a simple and straightforward solution for filtering YouTube comments and maintaining a level of sanity while browsing the platform.