Version relationships are quite similar, except that documents often require rather different sorts of change tracking since document formats are rather different from source code. Variant documents, in both cases, are often editorially derived from some version of an original, but once they are so derived, the variant usually takes on a life of its own, and acquires its own separate revision history. When this list first started 2 years ago, we referred to the configuration problem. This separation also makes sense in software configuration management, and also simplifies the problems by separating concerns. As the translation examples we've been tossing around show, the total problem of change in sets of related resources is terribly complex.
Variants represent human-derived, related but separate documents.
This typically includes the specification of cross-resource version relationships, like the fact that version 1.3.4 of the Englsih translation corresponds to rev. 2.0 of the German original, and such like. Not be be reflexively contradictory, but this is an easy no. Variants don't sensibly accomodate the kinds of operations that reasonable version handling demands. It's not as if it's sensible to ask for the diffs that transform a tex file into the coresponding .ps file because they are not editorially related.