Page source:

var fi = Wub_GetFunctionInfo("jw.publishedContent");
var content = WubEval(fi.exec);

num = ToInt(num);

var newC = content;

// content = [0,1,2,3,4];

newC = Select(content, 0, num) + [ [. "type"=type, "title"=title, "url"=url, "pos"=pos .] ] +
       Select(content, num+1, Size(content));

fi.exec := ToString(newC);

Wub_SaveFunctionInfo(fi);

WubCall("editContent", []);