Edit: It's been long enough that I can bump the warning off now.
The mature content warning is only so the page won't be spoiled in the thumbnail (since DeviantArt doesn't let you change your display thumbnail for anything that isn't an animation...). There won't be any warnings for strong (lmao and censored) language in the future. I just figured -- out of all the options to click -- it was the one most people wouldn't care about. : D