Page Edit is an Opera add-on that let you make changes to any HTML webpage.
To work with this add-on, simply open the toolbar popup UI and then click on the big toggle button at the left side. Once the add-on is active, the icon turns to blue color. A - Design Mode - banner will also be shown in the current tab at the top left corner. Now, the document is ready for editing; make desired changes with the text editing buttons available in toolbar popup UI. Once your edits are completed, click on the toggle button again to turn off the add-on.
Please note that, when active, this add-on is only working for the current tab. Moreover, it does not have any background activities when turned off. To work with text editing tools in toolbar popup, please first select a text (when the add-on is active) and then click on a desired text editing functions in toolbar popup UI.
If you found a bug to report, or have a feature request in mind, please fill the bug report form in the add-on's homepage (https://mybrowseraddon.com/page-edit.html).