From [What does the term "porcelain" mean in Git?](https://stackoverflow.com/a/6976506/3416774):
> "Porcelain" is the material from which toilets are usually made (and sometimes other fixtures such as washbasins). This is distinct from "plumbing" (the actual pipes and drains), where the porcelain provides a more user-friendly interface to the plumbing.
>
> Git uses this terminology in analogy, to separate the low-level commands that users don't usually need to use directly (the "plumbing") from the more user-friendly high level commands (the "porcelain").
As "plumbing" is a well-known term in Unix, I wonder why "porcelain" isn't popularized as well?
