The ~PSTMP extension is used to temporarily rename files that need to be deleted during real-time bi-directional replication. By renaming files to this extension, PeerSync will ignore them. This way PeerSync avoids oscillation of files.
If you remove the ~PSTMP extension from one of the files in your PeerSync Deletions folder, you will recover the actual deleted file. We have a method which can suppress ~PSTMP files from being created; however, we strongly recommend not using it when doing bi-directional replication. Without ~PSTMP files, you could see very strange behavior where files that are being renamed or deleted get re-added, perhaps overwriting important files.