It is shipped with Nokia's N800, N810 and N900 Internet Tablets, and is also available for the 770 via the 'Hacker Editions' of the operating system. In place of Mozilla's XUL-based user interface, MicroB uses the Maemo-native (GTK-based) Hildon API and widgets.
MicroB is Mozilla-based and uses the Gecko engine, but a number of features are omitted due to platform-specific limitations. In particular, SVG support is disabled due to unacceptable performance, and XUL is not included to reduce size and decrease memory consumption.[3] As XUL is not included, most Firefox plugins require porting and repackaging before they can be used with MicroB. In place of XUL, MicroB uses GTK and the Hildon UI toolkit to provide a native interface.[4]
Greasemonkey – All scripts that work on the desktop version of Firefox work fine in MicroB, extending the capabilities of the browser and even replacing the need for some extensions which are not available for MicroB.[9]