PDF datasheet, 234 KB, labelled SM5L1_3, which most likely covers a small family of related part numbers, though the name does not state the vendor or device type. The sheet should list each variant with its ratings, pinout and package dimensions. A technician uses it to identify a component by marking, check its limits against the circuit and pick the right variant as a replacement. Open it in any PDF reader, and confirm which member of the range matches the marking on the fitted part before using the values.
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 @datasheet_technar_org. 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.