The confusing part is that in many cases, end users are using NPM, pip, Go packaging, and to a lesser extent cargo etc to install finished end-user software. I've never written a line of JS but have installed all kinds of command line utilities with npm/npx.

Normally with an system package manager you would have a -lib package for using in your own code (or simply required by another package), a -src, and then a package without these suffixes would be some kind of executable binary.

But with npm and pip, I'm never sure whether a package installs binaries or not, and if it does, is it also usable as a library for other code or is it compiled? (Homebrew as you mentioned is source based but typically uses precompiled "bottles" in most cases, I think?) And then there is some stuff that's installed with npm but is not even javascript like font packages for webdev.

The other interesting thing about these language package managers is that they complete eliminate the role of the distribution in packaging a lot of end user software. Which ironically, in the oldest days you would download a source tarball and compile it yourself. So I guess its just a return to that approach but with go or cargo replacing wget and make.