Every Geocortex Essentials instance contains a Virtual Directory explicitly named "VirtualDirectory". Static content
in this directory can be accessed via HTTP. For example, if this is the default Geocortex Essentials instance on 
this server, then content in this Virtual Directory could be accessed using the following URL syntax:

http://<Host>/Geocortex/Essentials/REST/VirtualDirectory/

This directory can also be referenced in Site configuration files (Site.xml files) using the replacement token syntax:
{RestVirtualDirectoryUrl}. At runtime, this replacement token will be expanded to a URL similar to the one shown above.