POTUS and the Governor Kemp of Georgia have both requested a "signature audit" of the absentee ballot envelopes used in the Nov 3 Presidential election. Link
What would such an audit accomplish or prove?
ETA: My impression of the AJC article (coupled with some assumptions on my part) is that there are three signatures associated with GA absentee ballots process: 1) the original voter registration signature, 2) signature on the application for this years absentee ballot and 3) signature on the envelope containing the ballot.
So there are potentially three signatures that can be compared, one of which is potentially not as contemporaneous than the others.
Any signature comparison would be subjective in and of itself (just as comparison of driver's license photo is with a live and present person), so inherently the signature comparison is prone to some degree of error.
I further presume that these signatures have already been compared at various stages (registration versus application signatures at the application stage and application signature versus ballot envelope stage) by at least two different people.