Datasheet PDF for a part identified only as 1n4044, filed in the schematic category at 93.5 KB. The name gives no vendor, package or revision, so the exact device type and its issuer should be confirmed from the document itself before relying on it. Component sheets like this list pinout, electrical ratings and package outlines, which a technician uses to verify a marking found on a board, test the part correctly and select an equivalent with ratings at least as high as the original.
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.