Instagram Chat от bcattaneo

IMPORTANT NOTE (4/10/2020):
As of today, I see Instagram has enabled DM on the Web. I don't think this add-on is longer needed, unless you want to chat on a tiny bottom-right window, instead of the whole window.
Thanks to all who installed and submitted those friendly reviews!

This add-on allows you to chat on the Instagram Web app, which is not available by default although the functionality is there.

Functionality
Modifies the Instagram page doing the following:

1. Adds new chat icon on the top-right menu
2. Shows/hide a chat-box once you click on the new chat icon

How it's done
For a technical explanation, check this add-on's website or the "Technical Details" section.