This is a source-only release. Only Linux distributions that package Qt
5.12 need to use this release: it contains 


1) a workaround for 

   https://bugreports.qt.io/browse/QTBUG-72488

That is, an instant crash when using a tablet.

2) a workaround for a conflict between Qt's new xcb implementation and
Krita's xcb implementation

3) a fix to make Krita the top handler for .kra files on freedesktop-
based systems (https://bugs.kde.org/show_bug.cgi?id=337272)