Component sheet for the 3LN01M, a 41.2 KB PDF filed in the schematic category. The name is only a part code; sibling files 3LN01N and 3LN01C share the base number, so the final letter most likely distinguishes package or variant. Such a datasheet is used to verify terminal order, maximum voltage and current, and footprint dimensions when a small transistor on a board is suspected faulty. Any PDF reader opens it; compare the SMD marking and package shape on the PCB 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.