You can create custom prompts in about:config (search for browser.ml.chat.prompt), so you can use something like {"label":"Custom prompt","value":"%selection%"}. This %selection% is the text on the page that is currently selected. When you select something and click the chatbot popup button that appears and choose your custom prompt, it sends to the chatbot the string "<selection>the selected text</selection>". So instead of just returning the actual text, it adds the <selection> tag around it. There are two problems with this: 1. it's ugly, and 2. the chatbot doesn't ignore it, sometimes changing the response because of the "<selected>" tag. How to remove this tag so that what is sent is only the "the selected text" string with no tag?