Chatbot to what site? If there is chatbot Addon then it would be listed on Firefox Addon website and if not then there isn't one available for Firefox.

Hi

You can alter the size of the sidebar that the AI chatbot appears in by dragging the edge closest to the webpage.

The AI chatbot is a feature in Firefox and is not an add-on. If you are looking for an add-on based AI experience, I recommend that you have a look at https://addons.mozilla.org/en-GB/firefox/

More information about the chatbot in https://support.mozilla.org/en-US/kb/ai-chatbot