/usr/share/cli-common/packages.d/libgdk3.0-cil.installcligac is in libgdk3.0-cil 2.99.3-2+b1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1
/usr/lib/cli/gdk-sharp-3.0/gdk-sharp.dll