The X Window System by default uses the XDM display manager.

GDM allows users to customize or troubleshoot settings without having to resort to a command line.

GDM was written from scratch and does not contain any XDM or X Consortium code.

[5] Some of the copyright notices of GDM refer to the "Queen of England", whom release announcements from version 2.2.1 also named as a maintainer.

[7] Subsequently, developers realised that the title "Queen of England" has not existed since the Acts of Union of 1707.