ZIP archive of 4.49 MB for the Apple iPad Air 2. Its contents are not listed in the name, but a package of this size probably includes a schematic and possibly a boardview for the logic board. These documents let a technician trace power rails, check charging and display circuits, look up component values and locate test points. Check the board against the files before replacing parts, and note whether your unit is Wi-Fi only or cellular, since the documents may not cover both versions.
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 @cyberlanelectonik. Enginerys does not host this file.
How to open a .zip file
Compressed archive that every operating system opens without extra software.