It is written in the documentation for core-lightning:
Copy the contents of the $LIGHTNINGDIR to the BTRFS mount point.
Copy the entire directory, then chown -R the copy to the user who will run the lightningd.
If you are paranoid, run diff -r on both copies to check.
lightningd.sqlite3 and emergency.recover are binary files, as evidenced by file --mime-encoding. Is cmp a better tool than diff for checking integrity of channel backups? Isn't diff preferred for text files and cmp for binary files?