The upstream versions support Python 3 since a while. More details on: https://pygobject.readthedocs.io/en/latest/changelog.html Reproducible: Always
err, what you are linking to is pygobject, not pygtk. pygobject already supports python3, and the 3.34 version is just the GNOME 3.34 version that will be bumped together with the rest of GNOME 3.34 stuff. There is and will not be any python3 support in dev-python/pygtk, which is a dead unmaintained package that supports gtk2 with python2 only, and the replacement is pygobject:3 + gtk+[introspection], but requires code migration from the consumers. It even supports gtk2 with gtk+:2.0[introspection], if porting to gtk3 at the same time is too much work.
