IBM-labelled RAR archive of 1.58 MB named Yukon, which appears to be an internal project or platform code name, not a retail model. The name does not state which ThinkPad it belongs to, so match it to your machine by opening the documents and comparing the board markings. Typical contents are schematics used for tracing rails, verifying signals and locating components during board-level repair. Do not assume compatibility without confirming the board number on the PCB.
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.