I saw many links to TREESAME in the git log manual. But I did not know what that meant.
TREESAME
As stated in the same git -log manual , you mentioned:
Suppose you specify foo as <paths> . We will call commits that modify foo! TREESAME and the rest TREESAME. (In the diff filter for foo, they look different and equal respectively.)
<paths>
Given two or more trees, pathspec is considered TREESAME if and only if there is no noticeable difference for pathspec among the corresponding trees.
More intuitively, you can think of TREESAME as the same between trees.