How does the browser ask to open a particular application like this? Did it know this application is installed on my computer? enter image description here
the browser does not know whether or not you have the application that is shown, the browser is programmed, in case a protocol url (such as "steam://", "roblox://" among others) is opened, it does it with this box is shown, when an app is installed, for example, Roblox, when you install it, it installs together, a URL Protocol, which serves to run the program.
