You can easily view the definition of MoveToActor() by right clicking in Visual Studio and clicking Go To Definition. If you dig through you will find your answers.
Since you want to be so verbose, in line 932 of PathFollowingComponent.cpp, you will find your call to RequestDirectMove(), which it calls on the referenced movement component. On line 1185 of PathFollowingComponent.cpp you will find where it gets the reference to our TankMovementComponent via FindComponentByClass<UNavMovementComponent>().
So the execution flow is something like this:
MoveToActor() > MoveTo() > RequestPathAndMove() > RequestMove() > PathFollowingComponent->RequestMove() > SetMoveSegment() > Move segment is now updated. Meanwhile the PathFollowingComponent Tick is executing > FollowPathSegment() > MovementComponent->RequestDirectMove() > Tank moves accordingly.
So yes, all of this does indeed spit out a vector for our tank to move in, and that’s all that needs to be known at this stage in the curriculum. If you really want answers so badly just dig through the source code. I found all of this in like 5 minutes.