DevTools failed to load source map: Could not load content for http://127.0.0.1:5502/js/lib/underscore-min.map code example

Example: DevTools failed to load SourceMap: Could not load content for http://127.0.0.1:8000/bootstrap-select.min.js.map:

You need to go into Dev Tools settings and you need to unckeck 
"Enable JavaScript source maps"
"Enable CSS source maps"