from the website:https://pandoc.org/MANUAL.html#epub-metadata :

"EPUB metadata may be specified using the--epub-metadata option, but if the source document is Markdown, it is better to use aYAML metadata block. Here is an example:"

Perhaps it could be changed to:
"EPUB metadata may be specified using the--epub-metadata option, but if the source document is Markdown, it is better to use aYAML metadata block. Here is an example of the YAML metadata:"

Reason:
Most people, me included, do not know what epub metadata block looks like, or what yaml metadata block looks like. Since the title of this part of the manual is epub metadata, I assumed example is of epub metadata.
This addition clears the thing.

Describe your proposed improvement and the problem it solves.

Describe alternatives you've considered.