RAR archive labelled A710FD, which matches the Samsung Galaxy A7 (2016) dual-SIM model code SM-A710FD. The name gives no hint of the contents, which could be a schematic, a service manual or firmware, so open it and check before use. At 4.13 MB it is too small for a full stock ROM and is more likely documentation or a partial file. Confirm the exact model and board revision on the device label before relying on any diagram or flashing data from it.
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 @mobile_jump2. 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.
7-ZipWinRARThe Unarchiver (macOS)