Everything runs in this tab. Nothing is sent anywhere. The chain is
regtest, a private test network, so the coins are not real and there are no
peers to connect to.
Bitcoin Core's interface was drawn for a mouse and a big window, and starting it here downloads about 20 MB and holds it all in memory. On a phone it would cost you the download and still be unusable.
Open this page on a laptop or desktop instead. Nothing is downloaded until you do.