%PUBLIC_URL% editor warning on WebStorm
This article seems to give some more insght on this:
https://medium.com/@jenniferdobak/the-public-folder-and-favicons-in-create-react-app-8dc2cc1d492b
This is a good time to address that funky looking %PULIC_URL% tag. Remember the ‘escape hatch’ React provides in case we put assets in the public folder? During the build, assets prefixed with the %PULIC_URL% tag will be recognized and complied. However this is NOT best practice and should be used only when necessary.
Thus, in most cases, you can replace %PUBLIC_URL% with something like public, but of course, it depends on how you have structured your React project.