A 179 KB PDF for the 2SC3670, an NPN bipolar transistor by its JIS-style 2SC prefix. The name gives only the part number, with no device, board or revision, so treat it as a parts datasheet even though it is filed as a schematic. Repair work uses such a document to identify the base, collector and emitter pins, verify ratings against the circuit and pick a compatible equivalent. Always check the package type and the marking on the actual component before relying on the data.
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.