Over time, the EDAS permissions model had grown into a set of special cases, each motivated by a specific conference or journal request. (Each conference, for example, has different ideas of whether reviewers should see other reviews or reviewer identities, whether track chairs can accept or reject papers, whether authors are allowed to modify paper information after submission, or whether session chairs should be able to see reviews.)
We implemented a new permission model that defines roles such as chair, track chair or reviewer, and created a single configuration location, in Conference:Configure ("Permissions") to modify these permissions. There are a few special cases that can't be fit into that model, such as who can read papers or the conference program, but almost every other permission is now located there.
As part of the change, the role of webmaster has gone away, as it was essentially the same as the publication chair.