I'm german, but using english on all my games and this forum since this forum is international and it's also easier to use the "original" (english) names for everything, avoiding to learn two words when i need to learn english names of items anyway (and i hate ugly translations/names like "befeuerter ..."). of course, on german language videos (eg SeeNo) i post in german ...
about the "unknown key": all mod options have proper labels, but only 2 startup options have text when hovering the labels. i just looked at the locale.cfg files, and the english as well as the german version has 13 lines in the [mod-setting-name] section, but only 2 lines in the [mod-setting-description] section. the other 11 options show that "unknown key" message when hovering their labels.
ps: a bug in micro furnaces (crash on starting factorio) was just fixed and now it loads together with your mod, but together with that mod i also installed mini machines, and that crashes in its data-final-fixes when trying to start together with your mod. it really seems that it's difficult to get all of them to work together and I'll try restrict myself to mostly use QoL mods now (bottleneck, max rate, picker, etc) :-) but even with 3 or 4 conflicts, it isn't too bad: i tend to always use too many mods and thus it still works with 95% of my installed mods, LOL