So you've written a UNIX utility, library, or driver—or have started writing one—and you want to document your work in a manual. What happens next?
Practical UNIX Manuals: mdoc is a guide for writing portable and maintainable UNIX manuals (manpages) in the mdoc language.
Why mdoc? Formatters for the language are available by default on all modern UNIX installations and may be downloaded for non-UNIX systems. Furthermore, mdoc annotates content semantically, not presentationally, producing consistent manpages across systems. For an analysis of mdoc and competing formats, refer to Fixing on a Standard Language for UNIX Manuals, published in the USENIX magazine.
I also feature the History of UNIX Manpages http://manpages.bsd.lv/history.html , which chronicles the development of manpages from the 1960s to the present day.

Found via a post on the TUHS mailing list
https://minnie.tuhs.org/pipermail/tuhs/2019-September/018465.html

Found via a comment in the Raspberry π forum.

Manage multiple working trees attached to the same repository.
Found via https://fossil-scm.org/home/doc/trunk/www/fossil-v-git.wiki section "One vs. Many Check-outs per Repository"

A fully-free (as in libre) alternative to Github, found via
https://github.com/CodyReichert/awesome-cl

Vladimir Sedach explains how to establish a lisp machine keyboard layout under X11. He mentions that keycaps with the right symbols have been made.

A real-time journey through the first landing on the Moon
This website consists entirely of original historical mission material

Collection of short interviews with 14 Lisp programmers.

These steps describe a full disk (including /boot) encrypted setup on a non coreboot enabled system using the great grml live distro.

Abstract: The Breakthrough Starshot project proposes using radiation-pressure propulsion to send multiple spacecraft in the gram-range mass to interstellar targets. There are numerous engineering challenges to accomplishing this mission, but their project discusses speeds and accelerations previously only discussed for cannon projectiles and particle physics experiments. This article examines the problem from first principles to see if the project is even orders-of-magnitude possible. A preliminary check on their numbers seems to confirm that the project is possible in principle.
https://stkwans.blogspot.com/2012/04/program-66.html is about the Apollo guidance computer.
https://stkwans.blogspot.com/2012/09/a-review-of-adxl345-and-bma180.html