RAR archive of 2.82 MB for the IBM ThinkPad A20 and A22 notebook series. No board number, revision or description of the contents appears in the file name, so check after unpacking whether it holds schematics, boardview data or other repair references. Documentation for vintage ThinkPads like these is valued for tracing power rails, identifying obsolete components and locating test points during restoration. Verify that the planar fitted in your unit corresponds to the revision covered, since board versions changed across these model years.
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.