Long-term contributors. Influence higher level project development decisions. These people also weigh in on commit access decisions.
Trusted committers with ongoing commit access.
These are people who have been given commit access for a release cycle. After every cycle, their commit access expires, and their performance is reviewed by the Lead Developers. Developers generally have temporary commit access for a year before they are considered for permanent commit access.
Trusted developers who previously held permanent or temporary commit access.