Carefully understand the difference here and correct me anytime as I too am a human! 
The Tor Project team developed the Mullvad Browser which is managed by Mullvad VPN team which again as previously mentioned runs on en entirely different structure and requirement.
In Tor’s blog, they cited Mullvad VPN to be a “trusted” service. This is where the problem starts. Is this a right move to give Mullvad this level of certification by Tor team? If yes, then I have no issues as like many, I believe in the Tor network standards more than a VPN provider. I would start trusting Mullvad VPN too!
Mullvad Browser is deeply integrated with their VPN counterpart by design. Meaning this is more like a promotion itself for Mullvad’s VPN service. Homepage, Mullvad VPN extension, DNS, default bookmarks, designs etc all lead to Mullvad VPN service. This is, after all a browser made by the Mullvad team. You must understand here that everything matters including support.
Note the difference of action here. Mullvad used “same” support email address, managed by Google for both Mullvad Browser and VPN services while both must have been separate! Meaning even Mullvad Browser queries too ended up with Google!
Let me reiterate here again that their recent blog announcement left out “Google” and “Gmail” words and represented this as some “third-party” service that they had used. This is not a transparent move. You won’t even find these words under support category on their website anywhere! Should have been more transparent there.
My point here is that Mullvad is just another VPN service relying on revenues from users and therefore engage in such practices in order to mitigate a backlash. On one hand you talk about universal privacy and then for over a decade you kept on using Gmail as support, run by Google which is in the business of collecting user data and advertisements!
Any suppression of whole truth is a grave violation of trust. No matter how you spin it!
In an ideal situation, this browser should have maintained neutrality and not leaning towards any VPN service. Tomorrow if anything goes wrong with Mullvad VPN’s credibility, the browser will too lose its trustworthiness. To be honest this also means Mullvad’s past history too and this a grey area and unknown territory.
The Tor Project’s work is extremely transparent and straightforward. A VPN service relies on many “moving parts” out of their direct control. Both can’t be compared.
So, does the Tor Project trust Mullvad VPN ergo everything that Mullvad team does? I really don’t know the answer to this so kindly share your thoughts on this.