This checks how your mobile carrier handles connections, for a home-network product we're testing. It takes about 10 seconds.
Please turn Wi-Fi off first, so this tests your mobile data.
The check asks three public network servers (Cloudflare, Google and Nextcloud) how your connection looks to them, so they see your connection's address, as any website does. The result isn't sent anywhere: it stays on this page until you copy it, and it shows no address. Please send it back, with your carrier's name.