Optional
cpgThe path to the .cpg file. cpg is optional, but needed if your dbf is in some weird (non utf8) encoding.
Optional
dbfThe path to the .dbf file. dbf is optional, but needed if you want attributes
Optional
prjThe path to the .prj file. prj is optional, but needed if your file is in some projection you don't want it in
The path to the .shp file
A description of what relevant files exist and where