>>50504
>Is there such a thing as a non-motorized military unit
Well the militaryland deployment map uses the "light infantry" icon for TDBs and not "motorized" or even "rifle" icon (these are used on the brigade composition page at certain units where it's appropriate).
>So do they try to cram more infantry per kilometer of frontline, or do they rotate battalions more often?
It seems they were mostly used as anchors to hold trenches and replace heavier units in this role, so those can go elsewhere and do more useful things. How the rotation is done I have no idea, did not really see any info on that, I did not looking for it either.