Preston won 5-0 at the weekend in a behind closed doors game. Their opposition have asked to remain anonymous! https://www.pnefc.net/news/2021/august/pne-end-pre-season-with-5-0-win-at-deepdale/
Yes, that appears to be the rumour on their forum. Man Utd pulled out of a friendly with Preston, and Burnley's u23s were available at short notice.
Burnleys u23s should have been playing Tranmere but they sent the first team instead in the end who should have been playing Notts Forest but that got called off due to Forest having covid in the team.