ZIP archive for the IBM ThinkPad T23 notebook, roughly 1.60 MB in size. Apart from the model, the name carries no board number, revision or list of included files, so extract it with any common archiver and check what it holds. Such packs usually contain schematics or service material used to follow power distribution, measure test points and identify components while repairing an older ThinkPad motherboard. Confirm that the board markings on the PCB correspond to the documents before trusting any component values or rail voltages.
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 .zip file
Compressed archive that every operating system opens without extra software.