Elisp: slash in identifiers

Question

What is the exact value of the slash in the identifier (e.g. function name)? Like here

I assume this will replace the namespace, but I would like to know how to use it. There will be a link to the documents; anyway, I could never find him myself.

Answer 1

Formally, it does not really matter, like - or underlining. Some use it instead of a dash as a "namespace delimiter", but Elisp has no namespaces except by convention.