This file is indexed.

/etc/apt/apt.conf.d/80-btrfs-snapshot is in apt-btrfs-snapshot 3.5.1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

1
DPkg::Pre-Invoke {"if [ -x /usr/bin/apt-btrfs-snapshot ] && apt-btrfs-snapshot supported; then apt-btrfs-snapshot snapshot; fi "; };