Magisk-based root archive for the J701F, built for Android 9 on binary U7, stored as a 19.9 MB file with a doubled tar extension. Magisk patches the boot image so the system partition stays untouched, which helps with later OTA handling. The duplicate extension may need renaming before Odin lists the file. Flash it in download mode only when the installed bootloader is U7 and OEM unlocking is on. Make a backup, because Knox trips and a factory reset may be required afterwards.
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.