Service manual in PDF for the LG K8 smartphone, model K350DS, the dual-SIM version. At 11.1 MB it likely includes block diagrams, schematics, component placement and troubleshooting flows typical of LG service documentation. Technicians use such manuals to trace charging, power and display circuits, find test points and identify parts when diagnosing a dead or faulty phone. Check that the model variant on the device label matches K350DS, since regional versions can differ in hardware.
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 @mobileshematic. 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.