Small 137 KB RAR archive named only after board number 09A21-1, which follows the Wistron numbering style used on ThinkPad T410 and T410i mainboards. The name gives no hint of its contents, but at this size it is most likely a boardview or similar layout file rather than a BIOS image. Open the archive to identify it; boardview files are read with tools like OpenBoardView or FlexBV to locate components, test points and nets. Confirm the PCB number and revision before relying on any data inside.
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 @schematicslaptop. 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.