Self-hosting

Essential

Self-hosting is the use of a computer program as part of the toolchain or operating system that produces new versions of that same program—for example, a that can compile its own source code. Self-hosting software is commonplace on personal computers and larger systems. Other programs that are typically self-hosting include kernels, assemblers, command-line interpreters and revision control software.

https://en.wikipedia.org/wiki/Self-hosting