-Def.: Shallow commits do have parents, but not in the shallow
+Shallow commits
+===============
+
+.Definition
+*********************************************************
+Shallow commits do have parents, but not in the shallow
repo, and therefore grafts are introduced pretending that
these commits have no parents.
+*********************************************************
The basic idea is to write the SHA1s of shallow commits into
$GIT_DIR/shallow, and handle its contents like the contents