PDF document of 94.9 KB for the 2SC5299, a JIS-registered NPN transistor designation. Although catalogued as a schematic, files named after a part number like this are normally manufacturer datasheets. Expect the pin assignment, package drawing, absolute maximum ratings and characteristic curves. Use it to verify the base, collector and emitter pins before in-circuit measurement, or to compare specifications when choosing a replacement. Confirm the part marking and package on the board match the document.
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.