When a new ONAP project is proposed the initial list of Committers is provided as part of the New Project Proposals template which is presented to the TSC for approval.   The specific wiki version of the Proposal at the time the Project is approved by the TSC defines the actual list of Committers approved for that project when it launches. 

However adding a new Committer or removing a Committer once the Project is approved is governed by Section 3.2.2 of the ONAP Technical Community Document

The ONAP Technical Community Document has the official language and specific details that must be adhered to. What is listed here is simply a process overview and not considered authoritative:

Adding a Committer

Most of the process to add a new Committer is automated. See Committer Promotion automation via INFO.yaml for the HOW-TO

Removing a Committer: