In the current kde-apps/kde4-l10n-16.04.3, there is a RDEPEND change from !<kde-apps/kde-l10n-${PV} to >=kde-apps/kde-l10n-${PV}. So, all of a sudden the KDE4 localization package depends on the KDE5 localization package which seems to depend on several kde-frameworks/* packages from KDE5. Is that just a typo in the ebuild or does this dependency really exist?
Yes it does, otherwise translations are incomplete. This is not about KDE SC 4 localisation, it is about localisation of the KDE Appliations release bundle.
Thanks for clarifying!