https://wiki.mozilla.org/MDN/Development/Contribute/Design
"Are you motivated to make software better? Do you have an eye for design, usability, or user experience? The Mozilla Developer Network is looking for motivated individuals to share their thoughts on changes we make to the site. ....
"Explore your options. Take a look at our progress board https://mdn.kanbanery.com/projects/32137/board/. Everything in the Design column is ready for discussion. Graphic design, usability, user experience, and even just opinion. Nothing it out of the question here."
Thought volunteers on this list might be interested in giving it a try!