[rmunn]

Unless E remained untouched because it was not rewritten, and ended up staying parented on B instead of getting reparented onto B'.

Which is usually not what you want; most of the time you want E', which is E reparented onto B'. But sometimes you want E to remain untouched and stay parented on the original B. Depends on the situation.

[jolmg]

Exactly, but the second graph where untouched E is reparented to B' is not something that git would allow.

[shepmaster]

Ah, good catch. That's more of a graphic issue and not what I was trying to express. Updated the OP.