Discussion on fork-point mode
-----------------------------
-After working on the `topic` branch created with `git checkout -b
+After working on the `topic` branch created with `git switch -c
topic origin/master`, the history of remote-tracking branch
`origin/master` may have been rewound and rebuilt, leading to a
history of this shape:
- o---B2
+ o---B2
/
---o---o---B1--o---o---o---B (origin/master)
\
- B0
+ B0
\
- D0---D1---D (topic)
+ D0---D1---D (topic)
where `origin/master` used to point at commits B0, B1, B2 and now it
points at B, and your `topic` branch was started on top of it back