By merging the v4.16-rc1 tag into the v4l-dvb tree, you have created an
unnecessary merge commit. The v4l-dvb tree was already contained in
v4.16-rc1, so a fast forward merge was possible, but explicitly merging
a signed tag will give you a commit instead. In this case, you could
have just reset your branch to v4.16-rc1 or merged v4.16-rc1^0.
Linus, this happens a bit after the merge window, so I am wondering
about the rational of not doing a fast forward merge when merging a
signed tag (I forget the reasoning).