In sensus plenior, linked stories are over laid with one another and then interpreted in light of Christ.
The story of Moses's death is a parallel story to Enoch. Moses 'went up' De 34:1 and was not seen again. In such story overlays, we can refer to any of the 'actors' portraying Christ without contradiction. Enoch and Moses are both types of Christ and so in referring back to the story of Moses, one may also say it is the story of Enoch.
As such, When Jude references "Enoch" he is literally referring to Moses and his complaints against Israel.
Deut 33:1 ¶ And this is the blessing, wherewith Moses the man of God blessed the children of Israel before his death.
2 And he said, The LORD came from Sinai, and rose up from Seir unto them; he shined forth from mount Paran, and he came with ten thousands of saints: from his right hand went a fiery law for them.
14 And Enoch [Moses] also, the seventh [completed one or fulfillment] from Adam, prophesied of these, saying, Behold, the Lord cometh with ten thousands of his saints,
15 ¶ To execute judgment upon all, and to convince all that are ungodly among them of all their ungodly deeds which they have ungodly committed, and of all their hard speeches which ungodly sinners have spoken against him.
16 These are murmurers, complainers, walking after their own lusts; and their mouth speaketh great swelling words, having men’s persons in admiration because of advantage.
If Jude was referring to Moses using the methods of sensus plenior, then there is no need to look for an extra-biblical text. As other specific extra-biblical books are brought up in specific questions, I think we can point to plausible biblical sources that can be called by an alternate name using the methods of SP.
This is not really given as an answer, but a starting point for more research on the specifics.