how to fetch/pull/extract data from dashboard widgets of RTC.

Depends how you can access the Widget.

1:
If its a built in Widget you have to access it externally.
Maybe its easier to just read the HTML-Label if you need that value.
But I do NOT suggest this!

2:
If it's your own code you just have to read the distinct value.
Then it depends on how this value is  set. Maybe Array.length.

I really don't get what you want to achieve since it's not that easy to access data inside a Widget. The other point is, that this value is only present when this particular widget is loaded. So it's kind of dangerous to build logic on that value.

 Hi Jonas,

Hy Krunal,

Ok I might have an Idea how you could achieve that use case.
But remember, I'm just useful for Javascript questions since I haven't that much experience on the client side Java API.

My steps to achieve that would be:
1: Build a query which represents the data I need.
2: Get the query data over XHR
  -Now you know exactly how much defects are in your system.
   Where do you store the information about the "Kilo Lines of Code"?
   If it's a value inside the defect it's also easy to calculate this because through the query you'll also have the different Workitems (defects in that case)

3: Display the whole thing in HTML the way you want.
1: How to detect how many Defects are in the System?

I'd suggest you to build this logic with a query.

2: Then load the query into your Widget with XHR.

Maybe you do wonder how could I access a query and its data?
This will do the trick
https://myServer.xy/application(This case ccm)/oslc/queries/queryID
https://myServer.xy/ccm/oslc/queries/_te5rttgzuhjit45

Logic
require -> "dojo/request/xhr"
require -> "dojo/Deferred"
getRequest: function(url, returnType, preventCache){
    returnType = (returnType) ? returnType : "text";
    preventCache = (preventCache) ? preventCache : false;
    //Header should be based on the return type
    var xhrHeader = {"accept":"application/xml"};
    var deferred = new Deferred();
    xhr(url, {
        handleAs: returnType,
        method: "GET",
        headers: xhrHeader,
        preventCache: preventCache,
        sync: false
    }).then(function(response){
        deferred.resolve(response);
    }, function(error){
        deferred.reject(error);
    });
    return deferred;
},