PDF of 59.1 KB labelled only 30BF and listed as a schematic, with no model, brand or board number provided. The short name is not very informative; it most likely refers to a component marking or part family, so the content should be checked before use. A sheet like this is used to identify a part, read its pinout and ratings, and find a compatible replacement. Any PDF reader opens it; confirm that the marking on the board matches what the document describes.
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.