Android: Mozilla is best known for its web browser, but the company also produces Firefox OS for a limited number of handsets. You can try some of its apps in Android with a little sideways thinking.
Much like Google Chrome, Firefox supports web apps -- the OS and apps are built with the same technology -- and this is how you can bring Firefox OS to Android. Apps work like browser extensions, so they take up very little room, making them ideal for older devices or those with limited storage. Download a copy of Firefox for Android from the Google Play Store, or update your existing copy to 29 or above.
Fire up Firefox and visit the Firefox Marketplace, the Firefox version of Google Play or the Chrome Web Store. Take a browse through the Marketplace and tap an app that takes your fancy. Just as with regular Android apps, Firefox OS apps let you know about the permissions they need, and you have to accept this before you install anything.
Although the apps require Firefox, they are treated like any other app you might get though Google Play. Shortcuts automatically appear on the home screen, and you can fire up any app you install without launching Firefox first.
It is still fairly early days for Firefox apps, but the current selection shows just how far web apps have come. They don't quite give the full Firefox OS experience, but you get a great feel for just what is possible, and of course there is cross-platform support so you can use the same apps on your mobile as on your desktop.