According to Amnesty International, the new Hong Kong security law "applies to everyone on the planet". I quote:
The wording of the Hong Kong national security law asserts jurisdiction over people who are not residents of Hong Kong and have never even set foot there. This means anyone on Earth, regardless of nationality or location, can technically be deemed to have violated this law and face arrest and prosecution if they are in a Chinese jurisdiction, even for transit. Accused foreign nationals who don’t permanently reside in Hong Kong can be deported even before any trial or verdict.
Social media companies, for example, can be asked to remove content deemed unacceptable by the Chinese government, even if these were posted outside of Hong Kong or if the companies’ offices and servers are located in other countries.
That seems so surreal. Are countries allowed to do this? Can country X legislate stuff like "anyone who tells a joke that denigrates citizens of country X will be prosecuted"?