Firefox OS Simulator is an add-on for the Firefox browser allowing you to run Mozilla's new operating system directly from your browser. You don't need to get your hands on a new mobile phone to get a glimpse of the Firefox OS, all you require to get started, is a PC connected to the internet and the Firefox web-browser!
Open Firefox and go to this page: https://addons.mozilla.org/en-US/firefox/addon/firefox-os-simulator/
Click on the "Add to FireFox" button to download the add-on.
When prompted, click on the Install button.
Once installed you can launch Firefox OS Simulator using the below method:
Click on the Firefox button > Web Developer > Firefox OS Simulator
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