Block is special stat type, because it needs to use different base value when weapon is equipped and different when there is no weapon or shield (blocking with hands).
By default base value of block is set to 50 (50% of damage is absorbed).
This value is stored in InitialBlockValue variable.
Macro UpdateBlockBaseValue updates block value from EquipmentComponent when active items are changing.
For example if shield is equipped it will return only block value from shield, otherwise from weapon, and if there is no weapon or shield equipped it will return false and InitialBlockValue will be used instead.