match the tree structure of A, instead of reading the trees at
the same level. This adjustment is also done to the common
ancestor tree.
+
+With the strategies that use 3-way merge (including the default, 'recursive'),
+if a change is made on both branches, but later reverted on one of the
+branches, that change will be present in the merged result; some people find
+this behavior confusing. It occurs because only the heads and the merge base
+are considered when performing a merge, not the individual commits. The merge
+algorithm therefore considers the reverted change as no change at all, and
+substitutes the changed version instead.