The cardboard is no longer there
Mainly twiggy, brashy, shrub clippings. Stuff that was too big to try to compost, so it got piled up.... Small twisted willow branches, ornamental quince, rose...Then the muck heap you can sort of see on the right was added (waste dung/straw from cattle trailer). That lot got covered in topsoil, which then washed off, so it now has a pile of grass clippings on top...