How to replace the desired web app icon.
When you install the web app on your mobile device, the Firebase Studio icon appears.
When you say web app, are you building a Next.js app using prototyper or are you starting with one of the templates?
If you’re using prototyper, switch to code view and take a look at src/app/favicon.ico to see if this is the icon that is appearing for you. Try changing it to something else. You can also take a look at https://nextjs.org/docs/app/api-reference/file-conventions/metadata/app-icons for more on app icons.