404 errors for plugin files

I installed the Google maps API and it’s mostly working. A couple of the icons seem to be missing in the map display, and when I look at the browser console I see these errors:

[Warning] google.maps.event.addDomListener() is deprecated, use the standard (js, line 274)
        addEventListener() method instead:
        https://developer.mozilla.org/docs/Web/API/EventTarget/addEventListener
  The feature will continue to work and there is no plan to decommission
  it.
[Error] Failed to load resource: the server responded with a status of 404 () (public-main.css.map, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (single-listing.js.map, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (google-map.js.map, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (envelope-o-solid.svg, line 0)

The icons that seem to be missing in the map display is the street view icon, and the location pin icon. The both show up with a blank rectangle.

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