Python eggs are very nice for deploying web applications (the content &
software modules). Suppose you have prepared some content as standalone
folder with sitemap.xmap and various XMLs inside it. If you package it as
egg and want to deploy it to your production environment, you will need a
way for mounting a sitemap located inside the egg, like this:

<map:pipeline>
  <map:match pattern="api/beta/**">
    <map:mount src="rawegg:mysite_api:/sitemap.xmap" uri-prefix="api/beta"/>
  </map:match>
</map:pipeline>

"Raw" means here that you access file content by directly reading files
stored on file system, not by retrieving data from sitemap pipe inside egg
by URI. egg: URI is much like block: URI in Apache Cocoon
<http://wiki.apache.org/cocoon/BlocksDefinition>, but differs in
deployment. An example of egg: URI could look like this:

<map:generate src="egg:mysite_api:/news/{request-param:id}"/>