Schematic archive for the J610F, most likely the Samsung Galaxy J6+ model code, though the brand is not stated in the name. The 1.51 MB ZIP probably holds PDF circuit diagrams. Phone schematics help trace PMIC rails, charging and USB lines, display and camera connectors, and locate parts behind a short or a dead power-on. Open the archive to see whether a board layout is included too. Compare the model code and board revision printed on the PCB with the document before trusting component positions.
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 @phoneSchematics. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.