Missing information in documentation for "Add Custom Variable"

1

Hi,

Can anyone please explain me the missing information in the documentation regarding,

[https://grafana.com/docs/grafana/latest/variables/variable-types/add-custom-variable/#enter-custom-options]

“You can include numbers, strings, other variables or key/value pairs separated by a colon.”

How can I add other variables what is the syntax.

Thank you.