Page Edit is a free Chrome extension developed by Keller that allows users to make changes to any HTML webpage. With this handy add-on, you can easily modify the content of webpages using a toolbar popup.

To start using Page Edit, simply open the toolbar popup UI and click on the large toggle button located on the left side. Once activated, the icon will turn blue, indicating that the add-on is active. Additionally, a "Design Mode" banner will appear in the top left corner of the current tab. This indicates that the webpage is now ready for editing. You can make desired changes using the text editing buttons available in the toolbar popup UI. After you have completed your edits, simply click the toggle button again to turn off the add-on.

Please note that in order to use the text editing tools in the toolbar popup UI, you must first select the text and then click on the desired button in the popup.