> There is extensive and well written documentation for all aspects of systemd so I'm going to call BS on your post.
As long as you are prepared for the rest of the world to call BS on what you say here, as well. (-:
It's only "extensive and well written" if one sets the bar for those two quite low, and has very lax standards for doco. Unfortunately, people often do set the bar low in the Linux world. But to those from other worlds the words that come to mind are "acceptable" and "mediocre". As someone else has already mentioned here, and as people have pointed out passim over the years, the expected as the norm quality of doco for the BSD world is noticeably a higher standard than in the Linux world.
But it's not the BSD world alone where the norm is higher. The norm for the commercial Unices is and was higher, too. A case in point:
I wrote https://news.ycombinator.com/item?id=11629824 a little while ago. Checking my recollection, I referred to several manual pages for the rlogin command. The HP-UX and Solaris manual pages for rlogin actually had whole subsections about escape sequences, beginning with the general notion then proceeding to specifics of the various individual sequences. The HP-UX manual even proceeds to discuss how to send the escape character onwards, and how to send escape sequences across a daisy-chain of rlogin sessions -- something that still applies to SSH today.
The Linux rlogin manual has 1 paragraph, doesn't mention that there's actually a general concept behind the specifics that it lists, doesn't discuss how to escape the escape character, and doesn't discuss daisy-chaining.
If you're just about to point to your Linux ssh manual as a counterexample and observe the treatment that it gives escape characters, as good as that of the HP-UX doco, then scroll to the bottom of the page and enjoy the fact that you're reading BSD doco written by BSD people. (-:
What aspects of systemd is not well documented? I am sure it exists, but if you're calling BS, better to be explicit.