Using XDG_DATA_DIRS to point to locally built copy of ksudoku game assets, I successfully tested the following:
# Generate a Killer type (i.e. a custom Sudoku variant) puzzle using defaults for difficulty/symmetry
# Reconfigured toolbars to add the Home Page action & invoke the Home Page action
# Save the puzzle/game file & Quit the application
# Reload the application and load the previously saved puzzle.