/usr/share/cli-common/packages.d/libgtk3.0-cil.installcligac is in libgtk3.0-cil 2.99.2-2ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
/usr/lib/cli/gtk-sharp-3.0/gtk-sharp.dll