the internal field name for "Title linked to item" is "LinkTitle" When added to a csr file though it's undefined.

function CustomItem(ctx) {
// Build a listitem entry for every item in the list.

var ret = "<div class='ms-rteFontSize-2 '>" + ctx.CurrentItem.LinkTitle + "<strong>" + ctx.CurrentItem.Start_x0020_Date + " </strong></div><br />";
return ret;}

How do I display the link title?