RAR package labelled FIC A550, without a stated revision or listed contents, roughly 709 KB in size. FIC is the Taiwanese ODM First International Computer, and A550 is the model or board designation given in the name. Archives of this kind in repair collections normally carry a schematic or similar service document, readable after extraction with WinRAR or 7-Zip. Since the revision is unknown, compare the board markings carefully with the document title block before using it to trace rails or identify components.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @IT_SERVICE_WORLD. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.