The JSON website uses very clear notations to describe the JSON syntax:
(source: json.org )
What is the name of this record? Is it just a graphical representation of the BPF or does it have its own name?
These are called Syntax Charts (or Railway Charts)
"is a way of representing context-free grammar. They are a graphical alternative to the Backsu-Naur form or EBNF"
they are called "railroad charts"