The YWMS plugin was originally designed and coded by Francisco R. Santos 
<frsantos@gmail.com> based on a equivalent perl script by Frederik Ramm 
<frederik@remote.org>, with many modifications by Gabriel Ebner 
<ge@gabrielebner.at>, Joerg Ostertag <openstreetmap@ostertag.name> and others.
Now it is maintained by the OpenStreetMap community.