Testing Beta1 of Krita 3.0 results in not being able to open. kra files in general. .kra is not even listed in the supported file formats in the dropdown when opening a file. Running krita 3.0 on ubuntu 15.10 with an appimage.
Could you please check http://files.kde.org/krita/3/linux/devbuilds/krita-3.0-Beta-master-048ea24-x86_64.appimage -- this contains a workaround for a bug in Qt 5.6 that broke the database with file types.
Hey, thank you for the fix, it worked :-). grtz, Bart
Yay!