This can also be thought of as the point at which two commits were merged.
Use `git bisect` treating the latest commit as the “bad” commit and one of the two commits as the “good” commit.
Then check ancestry using:
```sh
#!/bin/sh
! git merge-base --is-ancestor <first> @ || ! git merge-base --is-ancestor <second> @
```
> [!tip]
> Run this script using
>
> ```sh
> git bisect run command
> ```