https://github.com/edu の I'm a student. のところに次のように書いて送信した。例によって英語に自信ないけどとりあえず通じたからまあいいかと思う。
I am a student at *** high school in Tokyo, Japan.
I'd like a free micro plan for a project with my schoolmates.
I don't have any .edu email address because my school doesn't provide it for students but I can send you a copy of my student ID card if required.
1, 2 日後 GitHub からメールが返って来た。
Awesome! We've upgraded you to a micro account, which will be free for the next two years. We don't enforce collaboration limits, so any group projects you may encounter can be hosted via your account.
Spread the word -- we love giving free Micro accounts to students! Send them to: https://github.com/edu
Have an Octotastic day!