https://mullvad.net/en/help/partnerships-and-resellers/
The essence of the article:
Except that Malwarebytes Privacy is just some paint on top of Mullvad and various open-source tools, which would be a parasitic albeit fine behaviour if this was clearly disclosed (as Mullvad is (amusingly) doing on its website), but there is no mention of this whatsoever on Malwarebytes' one. Worse, they're using a possessive voice when talking about the servers (that are Mullvad's) and the code (mostly Wintun and wireguard-windows amongst other, to which they didn't contribute back a single line of code.
Speaking of code, it's shipping
7z.dll from 2018, licensed under LGPL, and some parts under BSD, violating this license. wintun.dll, from the Wintun project, without mentioning it, thus violating its license. Most of the embedded dependencies are from 2018, and subject to documented vulnerabilities:
OpenSSL 1.1.0h pcre2 7z, as mentioned above Poco 1.9.0