linking verbs - "This Page Intentionally Left Blank"

This sentence often appears in a "blank" page of books. Why there's no linking verb after the subject (Page)? e.g.:

This Page Was Intentionally Left Blank

If the adverb in the original sentence is removed, we only have:

This Page Left Blank

So I wonder why the original sentence without a linking verb often appears in books. Is it not odd without a linking verb? Based on my understanding of the original sentence, it means that the page left itself blank, which is odd for me.

Hope to get some clarifications about this.