/usr/share/gdm/greeter.dconf-defaults.md5sum is in gdm3 3.14.1-7.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 | e2279492b09aaf7846125ad66f358442 3.8_unstable
5e372c504c951d1ee2f578432de494f4 3.4_wheezy
|