Zip archive of 5.29 MB labelled only with the Huawei Y300 model name, so its exact contents are not stated. Packages like this for phones typically hold a schematic, a component layout or service notes, but nothing in the name confirms which. Open it and check what is inside before planning a repair around it. If it contains a schematic, use it to trace power rails, charging and display lines, and compare the board marking on your handset with the document, because carrier and regional variants of the same model can differ in layout.
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 @Schematics_Mobile. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.