Mullvad is a VPN service whose distinguishing property is structural rather than technical. Creating an account produces a randomly generated number and requires no email address, no username, and no personal detail of any kind.
That matters more than a privacy policy does, because a policy is a commitment about what a company will do with information it holds, while this is an arrangement in which the information was never collected. Payment can be made by methods that do not link to an identity, which extends the same principle to the one remaining point where most services acquire a real name. The Android application uses WireGuard, supports server selection by country and location, and includes split tunnelling so that chosen applications bypass the tunnel entirely, along with a switch that blocks traffic if the tunnel drops rather than allowing it to leave unprotected. The technical feature set is comparable to several competitors and is not the reason to choose it, since the account model is the part that is difficult for others to copy without changing their business.
The usual limitation applies regardless. Traffic is decrypted at the exit and the operator of that exit can see it, so this relocates trust from the local network to the provider rather than removing the need for trust. Accounts already logged into remain identified whatever the traffic appears to originate from.