Program F and Combi D are initialized banks from the factory. Their contents are are not overwritten by a factory reset. From the manual ...
About the data loaded by All (Preload PCG and Demo Songs)
When you execute All Preload PCG, the following data will be loaded:
• Program: Bank A, B, C, D, E
• Combination: Bank A, B, C
• Drum Kit: 00(INT)–31(INT)
• User Arpeggio Pattern: U0000(INT)–U899(INT)
• Global Setting
If you execute All (Preload PCG and Demo Songs), the demo songs will be loaded as well as the above data.
• Demo Song: S000–003
Only when executing All (Preload PCG and Demo Song)
Note: As with the other user songs, the Demo Song data will not remain in Sequencer mode when you turn off the power. You’ll need to load it again if necessary.