The IMSLOGR files contain the save areas and checkpoint IDs for Symbolic Checkpoint (CHKP) calls. The IMSLOGR files are created the first time a CHKP call is made, and appended for each subsequent CHKP call. It is read when a Symbolic Restart call (XRST) is issued to restore the program save areas. You should delete these files periodically as they could grow quite large; however, once deleted, you cannot use XRST calls to restart from the deleted checkpoints.
These files are created in the Listing folder of your Enterprise Developer project.