Okay so I did some research because I was also curious and I laughed at your comment because you’re asking if it’s illegal while we’re reading this illegally lol
Anyways the copyright laws doesn’t have laws on translation watermarks so it’s not illegal for the translator to not specify and it’s not illegal for anyone to put a watermark because what’s illegal is the fact that they translated it without owning the rights, if that makes sense so if the artist themselves didn’t translate it and someone who doesn’t own the manga does translates it (fan translations) and distributes it, that’s what’s illegal, it doesn’t matter if they put a watermark or not I hope that makes sense.
Hey, so not sure if I'm saying this right but isn't it illegal to put a watermark on a manhwa that isn't your own? The uploader put their watermark on the recent update and idk if I'm being a Karen for it dkjsjxnd please tell me if I'm wrong or is this just normal, to put that there..(▰˘˘▰)
I've seen other translators/uploaders put a watermark as well but they specifically put translations after their name, to indicate specifically that they're a translations group or whatever