The openCypher Implementers Group is using the mailing list for decisions from now on.
The process is described in a recent email:
and in greater detail in a slide deck referenced from that email:
First out using this new process is CIP2018-10-29 - EXISTS and IS NOT NULL (Pull Request #334) by Neo4j: https://groups.google.com/forum/#!topic/opencypher/cAccRlkHdp8
The gist of this CIP is to deprecate (and remove) the use of EXISTS as a predicate function (with semantics equivalent to IS NOT NULL), and use EXISTS only for existential subqueries.
If you are interested in getting involved, sign up to the openCypher mailing list: https://groups.google.com/forum/#!forum/opencypher
and comment/vote on the CIP, or provide feedback on the process.
Representing the openCypher Implementers Group and Neo4j