Your favicon is in project_root > public > favicon.ico.

|
`--- public
     |
     `--- favicon.ico

Removing it is hard as browser generally uses a cached favicon if it doesn't find anything.

I'd urge you to change it. Just replace the favicon.ico file with an image of your choice. You can even rename a png to favicon.ico and use it. Make sure you do a hard refresh. You have to burst cache to see that change.

If you want to go all in on this, generate a favicon using https://www.favicon-generator.org/

Try this:-

Change <link rel="shortcut icon" href="%PUBLIC_URL%/favicon.ico" /> to

<link rel="shortcut icon" href="/a.png" /> which should be not present by the way or try deleting the favicon 

You have to do all the above (or below), but you also need to clear your browsing history.