Help with understanding output files

Hi all,

I am exploring REST toolbox for analysing some data. I used the Functional Connectivity button on the REST GUI and entered the coordinates of one ROI and followed other instructions on the manual. The processing completed and I received following outputs.
1 txt file with prefix ROI_FCMap_
2 pairs of img and hdr files with prefix FCMap_ and zFCMap_
1 nii file with prefix fFCMap_