Firefox OS
Firefox OS is an open source mobile operating system which uses Linux and Mozilla's Gecko engine to run a user interface and set of applications written entirely in HTML, CSS and JavaScript.
Read about how to install Firefox OS and how to develop apps for it.
Firefox for Android
Firefox for Android is Mozilla's mobile web browser for Android devices. It's recently been rewritten to use Android's native UI, making it faster, leaner and more responsive. It provides support for powerful APIs to access device capabilities such as the camera and telephony stack.
Read about how to help create Firefox for Android, how to use its device APIs, and how to build mobile add-ons.
Mobile web development
Mobile devices have very different hardware characteristics from desktop or laptop computers, and many of the APIs used to work with them are still in the process of being standardized.
Read about how to develop web sites that look good on mobile devices and take advantage of the new possibilities they offer. Learn how to make sure your web site works well on different browsers.