[gdal-dev] Creation/read format question

[Tyler Mitchell]

Not sure how to describe it, but when gdal lists available formats, I see a few different ways that formats are marked as read, write, etc.
The "rw" and "ro" items are easy enough for me to understand, but what about:
"rov" 
"rw+v"
"rwv"
"rw+"
?

Does the "v" refer to support in VRTs perhaps?
Do  rw+v, rwv, rw+ all mean same thing?

Any tips appreciated :) 

Tyler