Part number 1SS312 is all this 123 KB PDF name reveals; no brand, laptop model or board revision is mentioned. Under JIS numbering, 1SS denotes small-signal diodes, a series heavily used by Toshiba, so the content is most likely a component datasheet labelled as a schematic. It helps when sourcing a replacement diode, since it lists package outline, pin assignment, marking and electrical limits. Check the laser marking on the original part and the footprint size before ordering or soldering a substitute.
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 .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.