RAR archive, 185 KB, for the UX32LA board, LN variant, revision 2.0 according to the name. The file type is not stated, but the small size suggests boardview data, so check after extracting. Boardview files open in tools such as OpenBoardView or FlexBV and show part locations, nets and test points. A sister archive exists for revision 1.1, so match the revision silkscreened on the motherboard to this 2.0 version. Parts and positions can differ between revisions.
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 @cyberlanelectonik. 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.