Line #2 seems to contradict lines #99-101:
% nl /boot/grub/grub.cfg | pee "head -n 6" "tail -n 5"
1 #
2 # DO NOT EDIT THIS FILE
3 #
4 # It is automatically generated by /usr/sbin/grub-mkconfig using templates
5 # from /etc/grub.d and settings from /etc/default/grub
6 #
98 ### BEGIN /etc/grub.d/40_custom ###
99 # This file provides an easy way to add custom menu entries. Simply type the
100 # menu entries you want to add after this comment. Be careful not to change
101 # the 'exec tail' line above.
102 ### END /etc/grub.d/40_custom ###
Line #2 mentions "THIS FILE" and line #99 mentions "This file", maybe the latter
refers to '40_custom'. Line #99 adds a "this comment".
H This H...