Back when the GNU project was starting, among the first things they rewrote as Free Software were:
- text editor / IDE (Emacs)
- assembler, linker, and compiler
IOW, they made tools that they needed to further develop Free Software without relying on proprietary tools.
They wanted their project to be self-hosting.
Nowadays, we have more free software than ever, but we develop it using github and Discord...
For people who care about, support, or build Free, Libre, and Open Source Software (FLOSS).