Question on unhoverRaw Function

line 35 ----------------------------------------------------------------------

        unhover.raw = function unhoverRaw(gd, evt) {
            var fullLayout = gd._fullLayout;
            var oldhoverdata = gd._hoverdata;
        if(!evt) evt = {};
        if(evt.target &&
            Events.triggerHandler(gd, 'plotly_beforehover', evt) === false) {  
            return;
        }

    .....

Why is it a ‘plotly_beforehover’ event?

So that users can do things like: