ArcGIS JS API is not working! E.g. including it as <script src="https://js.arcgis.com/3.20/"></script> it then makes requests for resources in the wrong case. For example, it makes a request for "https://js.arcgis.com/3.20/esri/Graphic.js" which returns a 404. It should be requesting "graphic.js" (lowercase) e.g. "https://js.arcgis.com/3.20/esri/graphic.js ". The lower-case variant is returned by ArcGIS' servers whereas the upper-case variant is not.
This didn't used to be a problem, but all the sudden it is. Not sure why configuration changed regarding how things on arcgis.com are hosted, but it should not care about the case of the path being requested.
Not sure what's going wrong. Here's a working Codepen using version 3.20 and adding graphics to a map:
Seems to work the same way as at the current version (3.30)