Insert Unique ID into page?

When creating a new page via the Admin, is it possible to have a random number created and stored in the markdown frontmatter for that page? Or some other way to create a unique id number stored within the markdown?

Currently there is no way to do it.

Thinking loud, it could be a form field that you add to a page blueprint, and if it's a new page it generates a new incremental ID, whose current maximum value would be stored in site.yaml for example.