I frequently get the following error when debugging scripts in chrome:
Failed to load resource: the server responded with a status of 404 (Not Found) :50519/favicon.ico
It does not seem to affect anything but?
I did not bother to create Favicons for applications running in a local web browser. No need for that.
Please see the many references on the Internet about what favicons are, for what they are used, why browsers report a warning in the console etc.