Inconsistent font naming Extra-Light vs. ExtraLight, Demi-Bold vs. DemiBold

[kno10]

Oswald-Extra-LightItalic.ttf:Family: Oswald
Oswald-Extra-LightItalic.ttf:Subfamily: Extra-Light

Oswald-ExtraLight.ttf:Family: Oswald
Oswald-ExtraLight.ttf:Subfamily: ExtraLight

Note that the italic and non-italic version have a different Subfamily, and thus will not be considered to be the same font by some tools.

[kno10]

Or in the 3.0 otf files, when using autoinst:

[ERROR] I've parsed both fonts/Oswald-Demi-Bold-Italic.otf
and fonts/Oswald-DemiBold.otf as

    Family:     Oswald
    Weight:     demibold
    Width:      regular
    Shape:      roman
    Size:       0-0

[ERROR] I've parsed both fonts/Oswald-Medium.otf
and fonts/Oswald-MediumItalic.otf as

    Family:     Oswald
    Weight:     medium
    Width:      regular
    Shape:      roman
    Size:       0-0

Here these twp are recognized as regular, not as italic.