The 2SC4429 is the only information carried by this 107 KB PDF name. Following Japanese JIS semiconductor numbering, 2SC stands for an NPN bipolar transistor, so the document should be a component datasheet rather than a laptop or board diagram. Such sheets give lead identification, case style and limit values that matter when replacing a burnt transistor in a power or signal stage. Read it with any PDF viewer and confirm that the code printed on the faulty part really corresponds to this number.
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.