Hello,
Welcome to the Google Summer of Code through phpMyAdmin. We're delighted you have decided to work with us. You've shown considerable effort with your proposals and contributions and we are looking forward to working together through the summer, and hopefully even after the summer.
I'm Isaac and the main project administrator. I've been with phpMyAdmin in some capacity since 2005. I'm located in the United States.
If you have a concern about your interactions with your mentor, I recommend approaching him, but if you wish you may reach out to me directly. Further, we have another project member, William Desportes williamdes@wdes.fr, who isn't a mentor of GSoC but is responsive if you have issues. You should probably only engage him if the mentors are unresponsive, but I find it's helpful to lay out these contingency plans before they would be needed.
In general, we prefer communication to be public. If you have questions or wish to confirm you ideas about the design or implementation or an aspect, we prefer for that to happen on the developer mailing list or corresponding Github issue, so that the discussion about a particular decision can be found in the future. Private matters or interactions with your mentor can take whatever form your mentor prefers, whether that's by direct email, Google Hangouts, Jabber, IRC, or something else.
General discussions intended for the group of mentors can be directed to gsoc-mentors-2019@phpmyadmin.net, but I don't expect you to need this very often.
Your mentor can help you find the proper branch to target with your work, but generally we're working towards phpMyAdmin 5.1, as I hope to release 5.0-alpha before the coding period begins. You'll submit pull requests much as you did during the application period.
If you have any trouble along the way, please let the development team know. We might not have the answers to your immediate problem, but we're here to help work through a solution.
Congratulations and best wishes, Isaac