project() call should always come AFTER cmake_minimum_required(). This caused various hard-to-debug issues when searching for packages. Newer CMake versions complain that compatibility is broken with v2.6
ConfigOptionFloatsNullable, ConfigOptionIntsNullable, ConfigOptionPercentsNullable, ConfigOptionBoolsNullable. retract override values were added to the Filament profile: vector of floats: "retract_length", "retract_lift", "retract_lift_above", "retract_lift_below", "retract_speed", "deretract_speed", "retract_restart_extra", "retract_before_travel", vector of bools: "retract_layer_change", "wipe" vector of percents: "retract_before_wipe"
The XS was left only for the unit / integration tests, and it links libslic3r only. No wxWidgets are allowed to be used from Perl starting from now.