PDF document for the 2SA1246 semiconductor, filed under schematics but named only by the part number, so it is most likely the component datasheet. Under the Japanese JIS numbering system, a 2SA prefix marks a PNP bipolar transistor. The file is small at 41.6 KB, which suggests a short sheet of a few pages. Use it to confirm pinout, maximum ratings and package before fitting a replacement, and compare the marking on the original part, since many transistors print a shortened code without the 2S.
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.