RAR archive of 5.22 MB named for troubleshooting, with a team tag but no device model mentioned. It probably holds repair guides, fault-finding diagrams or solution images, but the actual contents and target models can only be confirmed after extracting it with WinRAR or 7-Zip. Troubleshooting material of this kind typically marks the components and test points involved in common faults such as no charging or no display. Check that any diagram matches the exact model and board revision before working.
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 @schematic_mobiles. Enginerys does not host this file.
How to open a .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.