What is a modification?

[Robert Collins]

I may have the name wrong; its a plugin Aaron wrote - and nothing to
do with automatic merges; it aims to show a sensible 'what changed in
this branch' when a merge from trunk is done. That is, if the merge is
identical (modulo line offsets) to what happened on trunk since the
last synchronisation point, the incremental diff in the branch will be
empty. If some reconciliation happens (e.g. updating to a new API,
conflict resolution,whatever) then the diff along the branch for that
change will be shown - but not changes from trunk.

-Rob