In KiCad 5 the main unit of the grid was imperial / “mils”, the European “mm” was secondary, of course with lots of fractions
0.127 mm (5.00 mils).
After installing 6, it is the other way around: the primary grid unit is “mm”, smooth, without unnecessary fractions, the secondary inches.
0.1 mm - 0.039 in.
Although I grew up with the metric system: I don’t like it here.
How do I get back to the KiCad 5 setting?
I don’t really understand.
grid settings in pcbnew show both variants: see picture
grid settings for eeschema are much fewer entrys, but should anyway set to fixed 0,1" / 0,05". (apart from decorating-objects and/or text)
In both KiCad V5 and KiCad V6 the native resolution for the PCB is nanometers, and it uses 32bit integers, which results in a maximum PCB size of a bit over 4*4 meters. If you attempt to go near those limits, there are some weird zooming issues / bugs though.
More than the top half of V6.0.1 PCB grid choices are basically imperial dimensions.
The way they are expressed depends on which of “in” ,“mil” and “mm” you select on the left
Related to this:
I find this list unwieldy
long, so I’ve opened the pcbnew.json file in my configuration directory and removed a bunch of these, and also added a 1um grid.
(There are three such lists in that file, so pick the right one).