This was supposed to parody how some of Vim's default shortcuts just flat out do not work on non-US keyboards, because e.g. typing [ requires pressing AltGr+8 on German layouts, but Ctrl+AltGr+8 is not the same thing as Ctrl+[.
And yes, it was also a reference to the Gimli glider.
I'm Czech and I use the English layout with UCW accented letters accessible via AltGr. It's much more convenient than tke standard Czech keyboard, even outside of Vim.
And yes, it was also a reference to the Gimli glider.