Hunger Wall was a fortification project which had questionable strategical importance, but it allowed anyone to work there for food thus avoiding famine without handouts(might not be 100% historically accurate, but that's where the idiom comes from).
It is used as an euphemism for a work, which was only created for the purpose of employing people. The work itself doesn't necessarily have to to be boring or repetitive and I intentionally avoid the term "job", because it might be referring to a work you assign to your employees when you're in between paying customer projects and you don't want to lay off staff.
Up until recently I thought this term can be used in English, but apparently it's only used in Czech language.
Is there some similar idiom which is used in English? I guess I could say something like "useless work", but I'm looking for something more fitting and a little bit more punch.