Some OpenType fonts, feature alternate stylistic sets that can be selected via
additional CSS3 parameters.
I did some tests with embedded OTF fonts with alternate stylistic sets, but the font display didn't change in BookView mode. Am I right in assuming that QT 5.1.0 simply doesn't support
-webkit-font-feature-settings/font-feature-settings?
And while we're at the topic, is there any Windows freeware font viewer (other than FontForge) that offers a preview option for these special OpenType-only font features?