The openTypeOS2WeightClass value in the source UFOs should match the expected CSS weights for the style of the font (200 for ExtraLight and 900 for Black). Currently the weights match the interpolation design values in the designspace file. Since one of those interpolation design values is 0, ufoLib2 complains. Changing the weights in the UFO does not affect the build of the fonts, as the interpolation values are taken from the designspace file, no the UFOs.
This is due to the project family structure being set from before our processes supported axis-based families. It will get fixed when we switch the project to be axis-based, though that will not be for a while.
The
openTypeOS2WeightClass
value in the source UFOs should match the expected CSS weights for the style of the font (200 for ExtraLight and 900 for Black). Currently the weights match the interpolation design values in the designspace file. Since one of those interpolation design values is 0, ufoLib2 complains. Changing the weights in the UFO does not affect the build of the fonts, as the interpolation values are taken from the designspace file, no the UFOs.