Fixed: Error when DocumentViewer is rendered in cross-domain frame:
Uncaught DOMException: Failed to read a named property 'matchMedia' from 'Window':
Blocked a frame with origin "http://development"; from accessing a cross-origin frame.

Improved: Show explanatory error message when DocumentViewer host page is opened via local HTML file:
Viewer cannot be loaded when you load the HTML file locally (i.e. with a file:// URL).
This causes CORS errors due to JavaScript module (.mjs) security requirements of the browser.
You need to run through a local or remote web server (i.e. with a http:// or https:// URL).

Improved: Show explanatory error message when DocumentViewer host page and iframe is not same origin for some reason:
Viewer cannot be loaded because the iframe and the iframe's parent document are not "Same Origin".
If you did set a custom libraryPath, ensure it is same origin as this host page
or adjust your server's CORS settings to allow cross-domain access.