We’re at the stage right now with the HelpHub project where we are able to accommodate contributors more easily as well as have tasks for Contributor Days.
If you would like to contribute to HelpHub, then have a look through this guide: https://make.wordpress.org/docs/handbook/about-the-docs-team/current-docs-projects/helphub/ – the primary need right now is for people to get involved in migrating content from the Codex over to the HelpHub staging site.
If you have questions or want to know more about how you can work with HelpHub at your Contributor Day then feel free to ping me on Slack.