git-debrebase(5): Rework the description a bit

Mention whether branches and branch states are ff.  And describe the
breakwater.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

1 files changed, 26 insertions, 8 deletions

diff --git a/git-debrebase.5.pod b/git-debrebase.5.pod
index dce648e..f181a40 100644
--- a/git-debrebase.5.pod
+++ b/git-debrebase.5.pod
@@ -116,11 +116,13 @@ state,
 which means it has a more particular special form
 convenient for manipulating the delta queue.
 
-=head1 BRANCH CONTENTS
+=head1 BRANCH CONTENTS - DETAILED SPECIFICATION
 
 It is most convenient to describe the
-B<laundered>
-state first.
+B<breakwater>
+branch first.
+A breakwater is B<fast-forwarding>,
+but is not usually named by a ref.
 It contains B<in this order> (ancestors first):
 
 =over
@@ -151,6 +153,18 @@ Zero or more single-parent commits
 containing only packaging changes.
 (And no quilt patch changes.)
 
+=back
+
+The
+B<laundered>
+branch state is B<rebasing>.
+A laundered branch is based on a breakwater
+but also contains, additionally,
+B<after> the breakwater,
+a representation of the delta queue:
+
+=over
+
 =item Delta queue commits
 
 Zero or more single-parent commits
@@ -158,13 +172,14 @@ contaioning only changes to upstream files.
 
 =back
 
-The
+An
 B<unstitched>
 (unlaundered)
-branch state is the same,
+branch state is also B<rebasing>.
+It has the same contents as the laundered state,
 except that it may contain,
 additionally,
-in B<in any order>:
+in B<in any order but after the breakwater>:
 
 =over
 
@@ -188,9 +203,12 @@ they are deleted when branches are laundered.
 
 =back
 
-The
+Finally, an
 B<interchange>
-branch state is the same, but may additionally contain
+branch is B<fast forwarding>.
+It has the same contents as an
+unlaundered branch state,
+but may (and usually will) additionally contain
 (in some order,
 possibly intermixed with the extra commits
 which may be found on an unstitched unlaundered branch):