The "diff3" style looks like this:

           <<<<<<< HEAD
                sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, s->proj);
                assert(HASGRAPH(sc));
                sccs_sdelta(sc, sccs_ino(sc), file);
           ||||||| merged common ancestors
                sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, s->proj);
                assert(sc->tree);
                sccs_sdelta(sc, sc->tree, file);
           =======
                sc = sccs_init(file, INIT_NOCKSUM|INIT_SAVEPROJ, p);
                assert(sc->tree);
                sccs_sdelta(sc, sc->tree, file);
           >>>>>>> c4892343......

That contains the same information, but you have to parse it yourself and it is not nearly as fast to see what changed.

However, it is faster to edit since you don't need to remove the diff markers.