in src/main/java/org/apache/sling/installer/factories/configuration/impl/ConfigUtil.java [327:338]
public static void removeRedundantProperties(final Dictionary<String, Object> properties, final Dictionary<String, Object> base ) {
final Enumeration<String> keyEnum = base.keys();
while ( keyEnum.hasMoreElements() ) {
final String key = keyEnum.nextElement();
final Object value = base.get(key);
final Object newValue = properties.get(key);
if ( newValue != null && isSameValue(newValue, value)) {
properties.remove(key);
}
}
}