Add comment describing the use of -1 to mean "no extent"
Add comment describing the use of -1 to mean "no extent"

bozzmob/dxr,srenatus/dxr,pelmers/dxr,nrc/dxr,kleintom/dxr,srenatus/dxr,nrc/dxr,pelmers/dxr,jbradberry/dxr,nrc/dxr,pombredanne/dxr,pelmers/dxr,jay-z007/dxr,pelmers/dxr,kleintom/dxr,pombredanne/dxr,jay-z007/dxr,srenatus/dxr,KiemVM/Mozilla--dxr,bozzmob/dxr,bozzmob/dxr,bozzmob/dxr,pombredanne/dxr,pelmers/dxr,gartung/dxr,gartung/dxr,kleintom/dxr,nrc/dxr,bozzmob/dxr,jay-z007/dxr,pelmers/dxr,kleintom/dxr,jbradberry/dxr,pombredanne/dxr,jay-z007/dxr,bozzmob/dxr,srenatus/dxr,kleintom/dxr,jbradberry/dxr,KiemVM/Mozilla--dxr,jbradberry/dxr,nrc/dxr,pelmers/dxr,kleintom/dxr,jay-z007/dxr,jbradberry/dxr,jbradberry/dxr,pombredanne/dxr,pombredanne/dxr,gartung/dxr,srenatus/dxr,gartung/dxr,gartung/dxr,KiemVM/Mozilla--dxr,KiemVM/Mozilla--dxr,nrc/dxr,jay-z007/dxr,pombredanne/dxr,bozzmob/dxr,srenatus/dxr,gartung/dxr,kleintom/dxr,gartung/dxr,KiemVM/Mozilla--dxr,KiemVM/Mozilla--dxr,jbradberry/dxr,jay-z007/dxr