While loading locally hosted arcgis javascript api scripts via esri-loader, dojo injects into html this script tag:
<script type="text/javascript" charset="utf-8" src="http://localhost:8080/assets/arcgis-js-api/4.6/dojo/b.js"></script>
This happens only in Firefox, Edge, IE. dojo is not trying to load this script in Chrome.
Obviously such file does not exists. Firefox, IE, Edge throws run-time errors.
I've also posted this question at esri-loader github page:
Weird script load in Firefox & Edge [dojo/b.js] · Issue #98 · Esri/esri-loader · GitHub