I can see you can get url parameters by using Param("MyParam"). But how do you debug this? When you click the play button this does have a url parameter so how you develop you app where having url parameters is part of the application flow?
There are three ways to view/interact with a PowerApp:
To work with/debug the Param()
function, you can create a label in the app set to the param value, then open the app in either 2 or 3 above to view its value.