It's not lost on me that the lowbrow humour of some too strict translation and a throwaway sitcom joke people thought was funny back in 2007 could be a way to stave off linguistic homogeneity.
For the use of profanity the data in the paper seems to indicate that swearing is retained in the LLM rewritten examples. Profanity however is rather subjective could be anything from saying the more mundane "oh my god" and "damn" to the extreme "shit eating fucklungerer" or use of slurs, but it's unstated in the paper as to the severity of the profanity. It's the severity of it that's important though, as LLMs restrain themselves from using something like "shit eating fucklungerer" unless explicitly told to.