Peak Design Dual Plate format_4x5 It can hold a mirrorless

It can hold a mirrorless camera or a small SLR

It's possible that it's some kind of reference to the internet (the design is very early-2000s) but I don't know what this bag has to do with the internet other than the fact that you're reading this description

Internal dimensions are approximately 15x30x50cm

and we recommend one to provide camera positioning options- but the top fitting on this tripod is a 1/4" thread

Peak Design Dual Plate format_4x5 It can hold a mirrorlessThe Peak Design Dual Plate is a tripod plate designed to fit any Arca or Peak Design compatible quick release system. In excellent condition, with one Peak Design Anchor.