We should add them to the gitignore of 3.1 and 3.2:
$ git status
On branch develop
Your branch is up-to-date with 'p/develop'.
(use "git add <file>..." to include in what will be committed)
nothing added to commit but untracked files present (use "git add" to track)
$ git checkout develop-ascraeus
Branch develop-ascraeus set up to track remote branch develop-ascraeus from p.
Switched to a new branch 'develop-ascraeus'
On branch develop-ascraeus
Your branch is up-to-date with 'p/develop-ascraeus'.
I changed the description because we should ignore the whole directory instead.