It does! So far I can see the following:

- uBlock Origin included

- mullvad extension to force DNS (disabled if you don't grant it permissions)

- button for "new identity" that clears all cookies and restarts

- NoScript included, but some JS permitted.

- Fewer customization options than firefox to resist fingerprinting

- Bucketed/discretized screen size to resist fingerprinting

EDIT: hard facts: https://mullvad.net/en/browser/hard-facts