This information refers to the FTP version of Segments, and not the Xpresspressfeed version. All information is included on 'combined' data sets. You would need to use the combined segment files (they begin with "seg*").
comp.segcmpy: correspond to the Company File Data.
comp.segsrce: the Source File (it will give the "vintage" for the data).
comp.segcust: the Customer File Data.
comp.segdtail: the Segment File Data ( the type of segments).
comp.segitem: Accounting Data
comp.segnaics: Industrial classification for each segment
comp.seggeocd: Geographic Area Codes File.