Apple iPhone 8 Plus archive in RAR format, roughly 5.08 MB, whose name gives only the model and not the type of documents inside. Extract it to find out whether it holds schematics, a boardview, or other reference files. Such resources are used during logic board repair to locate components, trace rails and signal lines, and identify test points when checking for shorts or missing voltages. Boardview files open in dedicated viewer software and PDFs in any reader. Check that any board code listed matches the device before relying on values.
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.