According to https://binary-factory.kde.org/job/okular-stable-win32/21/consoleFull the .mo files seem to be being built, but they are not installed when installing the resulting windows .exe
Fixed with this commit in craft-blueprints-kde.git: commit 7bd680afbda264626810eb72380d4f9ff8202b20 Author: Kevin Funk <kfunk@kde.org> Date: Mon Sep 4 23:18:39 2017 +0200 Base okular's blacklist on default blacklist
Where can I find the default blacklist?
See applications_blacklist.txt in craft.git