What are glues/adhesives for cardboard boxes/crates made of? Open cardboard boxes/crates, often for foodstuffs, are often glued to hold their shape. What is the glue/adhesive made of?

I ask to know if it is biodegradable, such that it is suitable for composting/gardening.

My preliminary research seems to indicate polyvinyl acetate (PVA), which seems to biodegrade fast enough for my application.

See example box (from CTHOE at Wikimedia):


Sorry if this is the wrong Exchange, it seemed the most suitable for my question.
Because the glue is not in direct contact with food you can use basically any glue. And cardboard is easy to glue so there is no limitation. Packaging should be cheap and therefore I would not expect a biodegradable glue.