Hotkey >> X (during draw)
Yellow cut is for slicing. When used the drawn shape will be cut from the object.
In non-destructive mode it can be confusing when going into edit mode but the apply button in the topbar will make the slices real.
Behavior Apply slices
Applying slices on the fly can come in handy for modelling non-destructive and destructively at the same time. Sometimes you only want to apply the slice operation and keep the previous operations intact.