The switch to C++ is incredibly poorly justified. I don't care how much safer you think it is (and it really isn't), the language is way more complicated and error-prone and rewriting the code is ALWAYS going to introduce many, many bugs than would be found by simply maintaining the code. This guy also switched on -fpermissive as part of the process, which disables warnings which are there for a reason! This guy has also done a lot of lovely things like committing half-assed changes to master (the build breaks more often than it passes!) which have clearly undergone no review.
Anyone this person convinces to use and contribute his fork are going to take time and money (yes, money - the guy put up a Patreon campaign and BountySource page) away from GnuPG, which sorely needs it, as we all hopefully remember. Please do not use this, and I hope the authors give it up.