Repair archive for the Huawei Y300, a ZIP file of 5.29 MB. Only the model number is given in the name, so the exact documents inside are unknown until extracted; schematics or board layout pages in PDF are the usual contents for phone packs. A technician would use them to trace voltage lines, check the USB and charging path, find the power key and display signals, and isolate shorted capacitors. Verify that the board version stamped on your PCB corresponds to the drawings before replacing components based on them.
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 @tamirat_moobile. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.