branding directories within packages not taken into account by OF
The branding directory within OpenFlipper-packages (Package-XYZ/branding/) that might contain an alternative splash screen or program/toolbox icons is not considered by OpenFlipper. So right now, the only possibility to e.g. change the splash screen is to replace the respective files in the original branding directory in the OF root dir.
To upload designs, you'll need to enable LFS. More information