/usr/lib/x86_64-linux-gnu/perl5/5.26/Gnome2/Install/doctypes is in libgnome2-perl 1.046-3build2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | GnomeUIInfo Gnome2::UIInfo
time_t a timestamp
Gnome2PerlIconListFlags Gnome2::IconListFlags
|