I’m pretty sure they’re for absentees, as they have to match application and vote signatures. This is really bad for PA, as vote counting doesn’t start until the morning of the election, so there’s the temptation to just count all votes as in without checking signatures.
On the other hand, the election results are going to come in without a lot of these absentees, so it might seem that PA went solid red at first.
The best thing we can do is put pressure on Biden to concede.