This is a small change to the Look & Feel KCM Code to fix https://bugs.kde.org/show_bug.cgi?id=409015 by changing the Splash Screen changing code a little bit.
This revision makes Look & Feel check if the package has specified a Splash Screen, that it wants Plasma to change the user's current Splash Screen to, or not via the 'defaults' file and a check for the 'splashrc' 'Theme' value in there. If there isn't a value found it will revert back to the old method of applying Splash Screens - applying the Look & Feel name as the Splash Screen. If a value is found however, ksplashrc's Theme value will be set to that value instead of the Look & Feel's name.
The reason for having the fallback in this code to the old behaviour is that many popular Look & Feels, such as the Adapta Look & Feel, all rely on the fallback method of applying Splash Screens to have their Splash Screens be applied, and if the fallback isn't there nothing will then their currently applied Splash Screen simply won't change at all unless the Look & Feel package specifies a Splash Screen theme.