App shortcuts (Android) or Quick Actions (iOS) are options displayed when you long press the app icon on the homescreen.
On Android, you can drag them anywhere on the homescreen to create a shortcut to a specific feature of the app. On iOS they appear when you 3D Touch the app icon.
Currently, on Firefox Android, there is only "New tab" and "New private tab".
Adding QR code scan would allow quick scanning on a single tap without having to open Firefox, click the address bar and click "Scan".
One alternative would be to create a widget to do this.
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