diff --git a/git/repo/base.py b/git/repo/base.py
@@ -1042,11 +1042,19 @@ def active_branch(self) -> Head:
        :raise TypeError:
            If HEAD is detached.

        :return:
            :class:`~git.refs.head.Head` to the active branch
        """
-        # reveal_type(self.head.reference)  # => Reference
-        return self.head.reference

    def blame_incremental(self, rev: str | HEAD | None, file: str, **kwargs: Any) -> Iterator["BlameEntry"]:
        """Iterator for blame information for the given file at the given revision.

diff --git a/test/test_repo.py b/test/test_repo.py
@@ -962,6 +962,46 @@ def test_empty_repo(self, rw_dir):

        assert "BAD MESSAGE" not in contents, "log is corrupt"

    def test_merge_base(self):
        repo = self.rorepo
        c1 = "f6aa8d1"