Listed under schematics, this 94.5 KB PDF carries only the designation 2SJ276. Under the JIS system the 2SJ prefix belongs to P-channel FETs, so the file is almost certainly a datasheet for that transistor rather than a circuit diagram of a device. A technician reads it to learn the drain, gate and source pin order, voltage and current limits and package type, which matters when measuring a suspect part in circuit or picking an equivalent. Any standard PDF reader will display it without special software.
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.