Resin:import

resin:import imports a configuration file into the current tag. The configuration file will match the current context, the a resin:import file in a <web-app> will be an XML file with a <web-app> tag.

tag	meaning
fileset	a set of files to import
path	the file to import
optional	if true, the target is optional

The web.xml and resin-web.xml files are loaded with a resin:import tag in the conf/app-default.xml file.

app-default.xml

...
<web-app-default>
  ...
  <resin:import path="WEB-INF/web.xml" optional="true"/>
  <resin:import path="WEB-INF/resin-web.xml" optional="true"/>
</web-app-default>
...