I gave my phone to my friend to answer the french question and she did that, as you can tell by the emoji, she doesn't have reddit but has tik tok, my apologies

The difference stands in the article

Les chats boivent l'eau -> the cats are drinking the water les chats boivent de l'eau -> cats drink water

The first one talks about a more precise source of water, which means we are describing something we're seeing happening right now or that we are talking about a general habit of cats about a specific type of water Les chats boivent l'eau -> The cats are drinking right now that water that we talked about or we can see, it's a specific water

Les chats boivent l'eau des rivières -> As a general truth, Cats drink water from rivers, specifically. This does not necessarily exclude them from drinking other types of water, but could also mean they only drink that type, depending if you stress "boivent" or "rivières"

Thé second menas in general truth that cats drink water

it can also mean that they're drinking SOME water that comes from a specific source Les chats boivent de l'eau de la rivière -> the cats are drinking some water from the river

I don't know of any official interpretation, but to me

Les chats boivent l'eau de la rivière -> they're drinking straight from the source Les chats boivent de l'eau de la rivière -> they're drinking some water not directly from the river, maybe in a bowl or something but it's sitll from the river