Eagle is a software limited to Printed Circuit Design. It is shipped with extensive printed circuit board libraries and for a lot of commercial printed circuits parts a description in eagle format is suppliert by its vendor. With Version 6 of the Eagle software the file format was changed in a XML format which allows a simple reading and modification with any text editor.
The Eagle XML format can be used in any way by the LayoutEditor. The schematic and board files can be loaded as well the library can be used as component libraries. Also inside the EditComponent dialog in the SchematicEditor can import parts from the Eagle XML format. To do so just press the import button within this dialog and choose a library file and afterwards a component of this library. Beside the component import the printed circuit board foot print can be imported. All layers will be converted to the default PCBLayerSetup. The PCB file format design rules will be used. To perform an import simply open a .brd file with the OpenFile feature. As Eagle handles design rules different, all imports may need to be adjusted to your PCB technology. Don't use this import feature without additional validation! An export to the Eagle XML format is not supported.