Pseudepigrapha

The Jewish pseudepigrapha bear the names of Old Testament patriarchs, kings, or prophets.

Source: wiktionary

Now, the myth theory, as it happens, is neither made nor marred by any decision as to the spuriousness of the Pauline letters. The crucial point is that, whether early or late—and the dating of them as pseudepigrapha is a difficult matter—the cardinal epistles have been interpolated.

Source: wiktionary

The difference between a pseudepigraph and a peroration is that the peroration is composed by the author of the main message. A pseudepigraph is composed by a different author, trying to leave the impression that it was the same. Heb 13 is clearly a pseudepigraph.

Source: wiktionary

The title of her^([Clare K. Rothschild]) monograph Hebrews as Pseudepigraphon¹³ reflects one of her main claims: "Hebrews should be classified as a Pauline [my italics] pseudepigraphon," because "although Paul's name does not occur in the text, the postscript makes a claim to Paul's authorship, particularly through appropriation of autobiographical details of Paul's life as the author's own."

Source: wiktionary