Settings -> Configure Dolphin -> View Modes:
Choose "Custom Font", "Choose...": other font settings than preselected;
alter "Icon Size" slider positions;
click OK; OK;
=> note modified text font next to icons, icon sizes
Settings -> Configure Dolphin -> View Modes:
Click "Defaults"
=> check "Font" is reset to "System Font";
=> check "Icon Size" slider positions are reset to default positions;
click OK
=> check text font next to icons, icon sizes are reset to defaults