Only the transistor code 2SC3458 identifies this 114 KB PDF, which sits in the schematic category. The 2SC prefix follows the JIS convention for NPN bipolar transistors, pointing to a component datasheet. Use it when testing a suspect part with a meter, since knowing the pinout lets you check both junctions correctly, and when comparing ratings for a replacement. The body marking often reads C3458 alone; check any suffix letter, which can denote a gain grouping.
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.