Here are the instructions my old plugin tester had provided for adding the plugin.
<feature name="InAppBrowser">
<param name="ios-package" value="CDVInAppBrowser" />
</feature>
For example, my game needs the in-app browser as well as cross origin resource sharing and network access resources, so my config.xml looks like this:
<?xml version="1.0" encoding="UTF-8"?>
<widget xmlns="http://www.w3.org/ns/widgets" xmlns:gap="http://phonegap.com/ns/1.0" id="com.mycompanyname.drawthat" version="1.0.0.2">
<name>Draw That</name>
<description>Drawing game</description>
<author href="http://www.mycompanyname.com" email="editedout@editedout.com">Colby Sites</author>
<icon src="icon-128.png" width="128" height="128" />
<icon src="icon-256.png" width="256" height="256" gap:role="default" />
<preference name="permissions" value="none"/>
<preference name="android-targetSdkVersion" value="19" />
<feature name="http://api.phonegap.com/1.0/network"/>
<gap:plugin name="org.apache.cordova.media" />
<preference name="orientation" value="portrait" />
<preference name="fullscreen" value="true" />
<preference name="target-device" value="universal" />
<access origin="*" />
<feature name="NetworkStatus">
<param name="android-package" value="org.apache.cordova.NetworkManager" />
</feature>
<gap:plugin name="org.apache.cordova.inappbrowser" />
<plugins>
<plugin name="InAppBrowser" value="CDVInAppBrowser" />
</plugins>
<feature name="InAppBrowser">
<param name="ios-package" value="CDVInAppBrowser" />
</feature>
<!-- Optional splash screen image, e.g.: -->
<!-- <gap:splash src="splash.png" width="1024" height="768" /> -->
</widget>