But why would you want to retrieve such a version in the first place? What would be your use case? If an item is checked out, you can still read the item with its "versionless" uri and you will get it as such (checked-out (readonly)). Or to be more precise, you will get the last major version which was checked in. There's no need for explicitly reading the "checked-out version" by using "v0" for example.

I have seen errors thrown when a `RenderComponentPresentation` is called from Tom.Net for a checked out Component. The error message would say something about "-v0". Additionally, I believe you can also encounter the v0 when working with Event Systems for saving items in the initiated phase.