Datasheet covering the 2SA1806, stored as a 44.6 KB PDF whose name carries an E suffix, probably indicating an edition or language version of the document. Per the JIS scheme the 2SA prefix identifies a PNP bipolar transistor. It can be opened in any PDF viewer to check ratings, electrical characteristics and package pinout. Technicians use such data when testing a part out of circuit or matching a replacement, and should compare the marking on the board with the sheet before substituting.
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.