Does Validation-and-Serialization document's outdated?

[whtjs]

there's an paragraph

Validation will only be attempted if the content type is application-json, as described in the documentation for the content type parser.

but when i move to content type parser. and tried to find about validation or serialization. Can't find about it

[mcollina]

I don't really understand what you are looking for. But definitely, this is a bug. I've opened #5459 to track it.