Small PDF of 42.0 KB covering the 2SB1030, with an _E suffix that may mark a document edition, though the name does not say. JIS numbering places 2SB parts among PNP transistors for low-frequency use. Filed under schematics, the content is likely the component datasheet with package, pinout and electrical limits. Consult it when a power or driver transistor fails, to identify its leads and pick a compatible substitute, and double-check the board footprint because lead order varies by package.
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.