The website of Mullvad itself has essentially no identifying information, and that's fine and perfectly reasonable, it's just got to be part of your threat model of using the thing. Mozilla whitelabeling the service and giving it a well known reputation is another thing entirely.
Hmm... I may not fully understand what you're looking for. From their website:
"Who owns Mullvad?
The Mullvad VPN service is operated by Mullvad VPN AB which is a subsidiary of Amagicom AB. Both companies are 100% owned by founders Fredrik Strömberg and Daniel Berntsson."
Location, Company name, individual names of founders/owners. What other "identifying information" would satisfy?
I found their FAQ, blog and guides tremendously helpful, transparent and upfront. There's a wealth of info with just a couple of clicks.
I thought it's owner regularly comments / joins in on hacker news... I didn't feel like I don't know who's running it?
Edit : quick search turns two very relevant posts:
https://news.ycombinator.com/item?id=24169684
https://news.ycombinator.com/item?id=23567530