Yes, there are two complementary approaches. We can include other struts.xml file -format files from a bootstrap struts.xml file, or we can package a struts.xml files in a JAR. Or both.
By Include
A typical struts.xml files will have one or more include elements:
...
<struts>
<include file="struts-default.xml"/>
<include file="config-browser.xml"/>
<package name="default" extends="struts-default">
....
</package>
<include file="other.xml"/>
</struts>
See the <include> element documentation.
You can use
The first include element tells the framework to load the struts-default.xml, which it will find in the struts2.jar file. The struts-default.xml file defines the "standard" interceptor and result definitions.
You can put your own <include> elements in your struts.xml interchangeably with <package> elements. The configuration objects will be loaded in the order of appearance. The framework reads the configuration from top to bottom and adds objects as they are referenced.
...