The key to gmail describes what sh*t umbrellas are at google :
as a shit umbrella, the product managers protect the engineers from getting distracted. It’s not enough to be a “shit funnel” where they would pass some of the junk down to engineers, they need to fully protect the engineers.
No wonder google engineers accomplish great things : they just focus on their work !
[...] something that is seemingly very hard to let go of. In Agile teams, management is often seem as an umbrella protecting the team or as a coaches. Either way, they are helping the team attain it’s goal [...]