How To Use `Firefox` to take Mobile-first Screenshots *Fast* on Any OS

> If you don't _already_ have **`Firefox`** installed, download and install it: #9 "Install a Dev Browser"! Do it _now_! ⏳

Once you have **`Firefox`** installed, open the Application.

In the top-right corner of the Firefox window, click on the "3 Horizontal Lines" (pancakes) Menu, Then Click on "More tools":

In the "More Tools" sub-menu, click on "Customise Toolbar":

Drag the "Screenshot" icon to your toolbar:


You should end up with the following:


Once you have everything setup, it's easy to take full-screen screenshots by clicking on the "Screenshot" (scisors) icon
followed by "**Save full page**":


Once you've taken the screenshot, you can click "Copy":

And paste the screenshot into any GitHub Issue Comment:


This excludes all the browser chrome including the URL.