Indexed as a schematic, this 209 KB PDF is named after the 2SC2383, an NPN transistor in the Japanese JIS 2SC series. The file most likely contains the manufacturer datasheet with ratings tables, characteristic curves and package drawings. During repair it helps confirm whether a measured fault is consistent with the part's specifications. It also guides the choice of a replacement with equal or better voltage, current and power limits, and the correct lead order.
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.