Exception in console when adding layout-card.js


I have small issue plugin layout-card.js
I’ve added the layout-card.js to location /config/www/plugins/
Then I’ve added it as JS Module in Lovelace resources.
I see that it’s loaded in browser network.
But then in console I see:

layout-card.js:1 Failed to load module script: The server responded with a non-JavaScript MIME type of “text/html”. Strict MIME type checking is enforced for module scripts per HTML spec.
Uncaught (in promise)

Any ideas more than welcome.