How can I add dc:source to simple search box through *-config.xml file?

[ben-Nabiy_Derus]

I am trying to update the simple search to return results that match the defaults, as well as to pull from dc:source field. What is the proper format of a contribution xml extension to do such a thing?

[ben-Nabiy_Derus]

This is version 5.5, by the way. I plan on upgrading to 5.6 or 5.7.2 in the near future.