Add To Homescreen (ATH) is a javascript widget that opens an overlaying message inviting the user to add the web site/application to the home screen. This was born mainly to support web-app-capable applications but extended to a more general purpose use case.
While this gist has been shared and followed for years, I regret not giving more background. It was originally a gist for the engineering org I was in, not a "general suggestion" for any React app.
Typically I avoid folders altogether. Heck, I even avoid new files. If I can build an app with one 2000 line file I will. New files and folders are a pain.