How to get the names of git branches which were merged into a merge

Question

We develop feature branches which we merge to master and delete. Then we merge master to a branch named "release".

Having checked out the release branch head, I need to see the names of all the branches that were merged to master and deleted.

I try the following but it only gives me the names of the branches that still exist.

git branch --list -a --merged

Answer 1

The default commit message in a merge includes the names of both the merged branch and the target branch. Have you checked there?

Something like Merge branch 'feature1' into develop .