To change the "dashlets" of site content:
you need to add <filter type="editingOthers" />to filedocsummary.get.config.xml
And add filter.editingOthers=Modified By Othersto the filedocsummary.get_en.properties
After that, you may have to modify the web script to find the right parameter for your dashlet. To do this, make changes to the file doclist.get.jslocated at alfresco\tomcat\webapps\alfresco\WEB-INF\classes\alfresco\templates\webscripts\org\alfresco\slingshot\documentlibrary\doclist.get.js.
: https://wiki.alfresco.com/wiki/Web_Scripts#Advanced_Implementations