All projects have a quite gigantic payload of backward compatible jQuery.
To switch to jQuery 3.0 reference the CDN version in your head tag:
At this point you now have 2 versions of jQuery, which is even worse. You need to replace the built in jQuery payload with a stub because other packages have jQuery as a dependency and they don’t acknowledge the jQuery in the head tag:
Create a folder in your project directory called packages. If you use local packages (you should if you haven’t adopted the modules system yet) then you’ll already have this folder.
Create a dir named jquery and place a file named package.js in it and paste in the follwing contents:
Boom, you’ve just removed 100 KB+ off your payload.