If you are looking for information about Pluggable Transports, the Pluggable Transports website has up-to-date information: https://www.pluggabletransports.info/

If you want to follow the specification process, drafts and proposal are available here: https://github.com/Pluggable-Transports/Pluggable-Transports-spec

The current stable version of the specification is PT 2.0: https://github.com/Pluggable-Transports/Pluggable-Transports-spec/blob/master/releases/pt-2_0.pdf

The current draft of the next version being working on is PT 2.1 draft 1: https://github.com/Pluggable-Transports/Pluggable-Transports-spec/tree/master/releases/PTSpecV2.1Draft1