RAR archive for the Gigabyte Aorus GA-RX5LXC at board revision 2.0. The name does not say whether it holds a schematic, boardview, BIOS or a combination, so inspect the contents before planning work. Gigabyte prints the model and revision on the PCB, and matching both matters because component layouts can change between revisions. Repair packs like this are typically used to trace rails, locate components and test points, and confirm part values when replacing failed regulators or MOSFETs.
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 @schematics_boardview. 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.