However first we need to discuss the understanding of that term:
"Linux" is mostly refered too as being the kernel, and well there is the "mainline" (kernel.org) Linux Kernel.
But I think the post meant "Standard Linux" in the sense of at least a userland.
The term userland could be extended to a plethora of wayland, X, KDE, Gnome, Mate, and what not .. but that discussion would take away the focus, so I for my self will define Standard Linux now
define:
A Kernel compiled with default config with a basic minimal set of userland that enable a person or an automation system to build or install all other software needed, from there on.
And basically we have that with LFS:
https://www.linuxfromscratch.o...
However with the basic requirement of at first build the build environment. The advent of LFS was nearly revolutionary, but that is now forgotten.
My take is: whoever has gotten through the manual process of downloading all packages, building LFS, and operating it will gain a deeper understanding of the basic problem with the "basic Standard Linux Distribution" "b.S.L.D." along the different licenses the packages carry.
But I would like to take the time to have you take a look at the FreeBSD src tree (user land in this case)
https://github.com/freebsd/fre...
What might interest you is the naming of the sub-directories named for example "cat", "cp", "dd", .. actually the names of your favourite userland tools that I think would define also "Linux" to you.
And when you enter one of such directories you will spot:
1.) make-file
2.) make-dependency-file
3.) a. ".1" file, which is the man-page for the tool
4.) a ".c" file
FreeBSD has every userland tool that for Linux is divided into many sub-src-"packages" - read LFS-book for a better term - inside this source tree.
And when you'd want to learn about the operation of a command you can just open it up in "vi", even edit it and just call make / make install when inside the corresponding directory and then you will have your own version of the corresponding tool
"How does vi-work" - look here:
https://github.com/freebsd/fre...
btw. "freebsd-update" for example can also update the src-components, not only the binaries
And when you'd want to take a look at the package manager:
https://github.com/freebsd/fre...
which handles everything aside from the kernel and basic userland.