/usr/bin/nrefactory-demo-gtk is in nrefactory-samples 5.3.0+20130718.73b6d0f-3.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 | #!/bin/sh
exec /usr/bin/cli /usr/lib/nrefactory-samples/ICSharpCode.NRefactory.GtkDemo.exe "$@"
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