

You’re right, I was just going on the post saying “With the WiFi4EU app, you can access…”, implying that you need the app to access it. But on their webpage it spells it out more clearly:
On connecting to the free Wi-Fi network for the first time, you will be redirected to a secure login page (a captive portal). You will be able to sign in with a simple click-to-connect functionality.
The app is just a map, the WiFi connection uses a standard SSID and login portal.