/etc/debootstrap/locale.gen is in grml-debootstrap 0.81.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | # This file lists locales that you wish to have built. You can find a list
# of valid supported locales at /usr/share/i18n/SUPPORTED, and you can add
# user defined locales to /usr/local/share/i18n/SUPPORTED. If you change
# this file, you need to rerun locale-gen.
en_US.UTF-8 UTF-8
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