A 129 KB PDF filed under schematics, though its name, 2SC3807, is simply a transistor type number. Under the JIS designation system the 2SC prefix denotes an NPN transistor, so expect datasheet content such as pin assignment, maximum ratings and characteristic curves. No manufacturer or package is stated in the name. Use it to identify the base, collector and emitter leads before testing in circuit or with a diode-mode meter, and compare the case marking on the part you hold against the document before ordering a replacement.
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.