I don't know the answer, but there are two ways to take it:
1. Submarining to destroy confidence in an actually trustworthy, decent VPN company
2. They're an intelligence front.
For me, Mullvad have the appearance of the greatest likelihood of being legit since they're not aggressively pushing their product with lies and fear mongering. That gels with my vibe. If they're an intelligence front, well, most VPNs probably are as well, so I'm no worse off.
Luckily I'm not doing anything that would get me in the kind of trouble for which multi-jurisdictional cooperation is worthwhile.