@JosephWright and @PhelypeOleinik currently the kernel code uses \tex_expanded:D directly on a few locations (my bad -- but you accepted the PRs so your fault). And I guess since L3 doesn't yet require\expanded that is fine for now, but looking at macros like \__kernel_exp_not:w it one should consider migrating the \tex_expanded:D code to some \__kernel_expanded:w some time in the future.
@PauloCereda At first I read BeeOS and was expecting an OS with a little bee instead of a mouse pointer :)
@PauloCereda Last week I listened to a podcast in which the American host struggled with the pronunciation - I bet she wouldn't mind if we would get rid of it :)