Apple iPhone 5s repair archive in RAR format, a large 45.0 MB package whose name gives only the model. At this size it may contain schematics, boardview files and related documents, but the contents are not stated, so verify after extraction. iPhone schematics and boardviews let technicians trace power rails, locate components on the logic board and find test points for diagnosing shorts. Boardview files open in dedicated viewers; confirm the logic board number printed on your board matches the files.
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 .rar file
Compressed archive — the usual wrapper for a schematic + boardview pair or a BIOS + EC set.