The basic fabric, Pertex Equilibrium, is used in other “light softshell” pants (MacPac), which has been around for awhile (reviews ~ 2016 call it “heavy” actually) at 167 g/m2 .. but if reading this product page correct, .. these pants are 55 g/m2 with a combination of 20d and 40d threads in an irregular pattern to keep contact minimal with skin. That and upgraded to the waist closure, all the pockets (worn weight help for the lighterpack!), etc..
Going with meshy Champion brand shorts myself at $10 USD, but if these are truly light, decent SPF….
(note superscript did not transfer for square meter = m2)