If you want to help out, these are the groups you can join:

Core

The core working group will find accessibility issues, write and discuss tickets on core trac and write code patches for WordPress core. Contact: Andrea Fercia (@afercia)

Documentation

The documentation working group will write documentation about accessibility in our Handbook and on other relevant places on WordPress.org. Contact: Rian Rietveld (@rianrietveld)

Theme team

The Theme team will review themes for the WordPress.org repo labeled with the accessibility-ready tag and the new core themes. Contact: Joe Dolson (@joedolson)

Meta

The Meta team will find accessibility issues, write and discuss tickets on meta trac and code patches for the website WordPress.org and WordPress.tv.Contact Joe Dolson (@joedolson)

WordCamp themes

The WordCamp themes working group will review of the WordCamp themes and help with fixing the accessibility. Contact: David Kennedy (@davidakennedy)

Test team

The Test Team will test the accessibility of new and existing functionality in and for WordPress core, at the request of the other workgroups and teams. Contact: Rian Rietveld (@rianrietveld)