Maintainers team

An open project like Aegir can always use more contributors.

We have a core aegir team that is in it for the long run and pretty solid.
What we would like to strengthen is the team of people maintaining key
contrib modules used to make Aegir what it is.

The #2180053: Include more "golden" contrib issue is one step to spread the maintainership role.
It seems less scary / invasive to feel responsible for a part of Aegir
then the whole.