Seriously, I am unable to really find much about them outside of short lines from Marx and Mao about their potential destructiveness among other things, but I still do not really know what that “class” is. It seems to refer to the poorest members of society that includes unemployed, criminals, homeless, etc… And are they really so incapable of being utilized in revolutionary activities as they are portrayed?
Edit: By “destructiveness”, I refer to how Marx and Mao portrayed them as people that are not considered reliable allies in any proletarian revolution (though even this understanding might be wrong because I think the explanations about them are vague).
MLs posit that the socialized mode of production under capitalism puts workers in a position where they can grab political power by organizing. The lumpen who exist outside of traditional employment as well as the law are a potential source of counterrevolution. For the imperialists, they are a natural ally/power base, a route to enter a territory. Just look at the zionists using gangs in Gaza to loot aid trucks. Or the americans allying with opium growers in Afghanistan. Or the british getting the Chinese addicted to opium. The first thing the FLN did was go after pimps and drug dealers.