To modify “site content” dashlets:
you need to add <filter type="editingOthers" />
in file docsummary.get.config.xml
And add filter.editingOthers=Modified By Others
in file docsummary.get_en.properties
After this you may have to change web script to search desired parameter for your dashlet. For that make changes in doclist.get.js
file located in alfresco\tomcat\webapps\alfresco\WEB-INF\classes\alfresco\templates\webscripts\org\alfresco\slingshot\documentlibrary\doclist.get.js
.
For ref: https://wiki.alfresco.com/wiki/Web_Scripts#Advanced_Implementations