A small observation. I use mobile Firefox (Fennec actually) and I accidentally hit this tiny feature today. The Wyze forum site is, for some reason, the only site I visit that seems to manifest a Home icon button in the URL bar. The function seems identical to the browser’s settings, Page, Add Page Shortcut option. It just adds a URL shortcut to one of my Android home screens.
FYI I found the documentation on this feature.