For example, the story of the resurrection has some differing details which are independent from all the other historical documents we have. Perhaps most obvious is how the author of Peter puts the blame of Jesus’s death onto Herod as opposed to Pontius Pilate which is more common among the other Synoptic Gospels. This change in details does give us a glimpse at the author of Peter because it shows who his audience was and who he was trying to appeal to at the time.
Another interesting thing about Peters Gospel in particular is that all of his stories are unique to his Gospel only. Therefore, scholars can determine that he likely didn’t use the other Synoptic Gospels as a source. This then begs the question of who wrote the Gospel of Peter and what sources the author used when writing it. On the other hand, his Gospel does have similar themes to those expressed in John. Without having these sources at hand it is likely that Peter wrote much of his Gospel solely of remembering what he had