We describe a debugger for functional logic computations.  The
debugger is an accessory of a virtual machine currently under
development.  A distinctive feature of this machine is its
operational completeness of computations, which places novel
demands on a debugger.  We give an overview of the debugger's
features, in particular the handling of non-determinism, the
ability to control non-deterministic steps, to remove context
information, to toggle eager evaluation, and to set breakpoints on
both functions and terms.  We briefly describe the debugger's
architecture and its interaction with the associated virtual
machine.  Finally, we describe a short debugging session of a
defective program to show in action debugger features and window
screenshots.