All that is is a Visual Basic Form holding an ActiveX Web Browser Object as a simple one-shot IE browser window to open with the PN URL inserted in to the code, instead of a Textbox which would take the URL as typed, insert that URL to a variable (A Dim in VBScript) and then take it as a URL either directly from the TextBox or from the variable. Either should work.
Java and Android both have a similar Object, one that will image web pages in a JFrame or Android equivalent.
The thing about a web app is that, in Windows it runs exactly like my BrowserBum.exe, borrowing from the IE installation to run.
In Java or Android, the script calls for the web browser library to create the browser and control Objects in a JFrame, a placeholder for the screen and the various controls.
An app may include custom controls, say for direct downloading and uploading of files from the PN download page, but technically speaking, an app is litte more than a direct Shortcut to a website.
A Shortcut to a website opens the browser or, as an app, calls the Java or Android libraries for creating the browser window and whatever custom controls, and then just goes to the site.