Andrew Abela: Extreme Presentations.
How to make a ticket How to propose a solution See Mark Jaquith‘s toolbox. Seems like the answer is: Log into http://make.wordpress.org Open Trac Find open tickets Propose solutions In a similar manner you can create tickets too.
At this point the developers of Twentyseventeen will focus on costum usability for the website maintainers. A ticket on developing costumize panels bykarmatosed is here.
The game is afoot.