This column indicates the internal major and minor revision (separated by a dot, in the form major.minor) of the Kickstart ROM. Major revisions represent major changes to the core code, corresponding with different Kickstart releases:

V24 - Kickstart 0.4? (found on "Velvet" board, had both V23 and V24 modules)
V27 - Kickstart 0.7
V28 - Kickstart 0.8?
V29 - Kickstart 0.9?
V30 - Kickstart 1.0
V31 - Kickstart 1.1 (NTSC)
V32 - Reserved for Kickstart 1.1 (PAL)
V33 - Kickstart 1.2
V34 - Kickstart 1.3
V35 - No Kickstart release, Jumpstart 1.4 (A2024/Hedley support)
V36 - Kickstart 1.4/early 2.0
V37 - Kickstart 2.0 (late)
V38 - No Kickstart release, Workbench only (Amiga OS 2.1)
V39 - Kickstart 3.0
V40 - Kickstart 3.1
V41 - Reserved for double-byte character release of Workbench 3.1 (not released)
V42 - Reserved for internal alpha of Workbench 3.2, parts of which were released with Envoy
V43 - No Kickstart release, modules by Amiga Technologies and others (SetPatch, etc.)
V44 - No Kickstart release, Workbench only (Amiga OS "3.5")
V45 - Amiga OS "3.9" (No Kickstart release, Workbench only) and "3.X" (Cloanto)

The minor revision represents smaller changes to the system, often to fix bugs or add small features. Commodore minor revisions almost always represent a "build" number, corresponding to the number of times the Kickstart ROM code was compiled to source (i.e., minor revision 175 represents the 175th time the core code was compiled for that major revision).

The internal revision often has a direct correlation with the revision of Exec contained within, but is not the same revision number. The revision of Exec can be seen in the detail provided with the KickInfo utility.