I just tested this again with a Kirby test site where it works, however, it does not seem to work with multi-language sites with which I tested it originally.
Sorry, I didn’t mean to undetermine the info, your PHP knowledge is obviously stronger than mine – I tested this locally as well and was simply wondering how the path information would be processed as an argument without mod_rewrite
That’s alright. 
I was also wondering how this could ever work when I first saw this pattern.
Hm, I didn’t test that. This smells like a bug. Could you please open an issue on GitHub with a few details? Thanks!
I confirmed that not being able to use rewrite=false for multi-language setups is a bug and fixed it over at GitHub: https://github.com/getkirby/kirby/pull/272
Meaning: You don’t need to have mod_rewrite to use the Kirby core, it is only required for the Panel.