Some curiosity that have bothered me: I have some others software in my PC that use the sch, lib and pro file extensions. KiCad use kicad_pcb and kicad_mod as file extension related to the layout software that solve all the cross use.
Why there is this disambiguation to the layout files but not to the schematic files? There is some future road map to change those? (kicad_sch, kicad_lib, kicad_pro)
I am asking because releases ago I remember to be part of a discussion to standardize the backup extension files, at that time: kicad_pcb -> kicad_pcb-bak but sch -> bak (just), and now also sch -> sch-bak