I've been using par for about twenty years, and 100% agree with its own apology: "Its only redeeming features are that it is extremely useful".
I literally have no clue what my $PAR* vars do, or what the odious string in my mutt config does. However, it works perfectly so I simply trust I won't have to figure it out again.
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Oh, and check out his X-Advice¹ doc. It was a really great idea that sadly never caught on. Scanning a years worth of my own mail to write this comment tells me it is just me and one friend who use it, and only for "should read whenever" for messages between eachother :/