Just seen that Opensky Network has relaunched the webpage new:
The map isn’t (yet) working, they missed using HTTPS on their beta. But if you remove the “beta” from the URL, you see the current map. They use the well known tar1090 for it.
You can login using your existing account, if you feed already, it should work. But lots of things aren’t working properly so far.
On my sensor page there are all old devices listed.