Calendar Transactions SFHC_FCAL, SFHC_HCAL, SFCH_HOL and SFHC_CONFIG

In S/4HANA, beside transactin SCAL for calendar maintenance, determination are 4 idiosyncratic transactions SFHC_FCAL, SFHC_HCAL, SFCH_HOL and SFHC_CONFIG (see attachment).

What is the usage of theses transactions? They don't amusement immoderate entries and determination is nary documentation for these customizing activites. In the Help Portal, determination is besides nary information.