Hongkongers are people who live in a place called Hong Kong. It's a big city in China, but it's kinda like its own little special place with its own rules and way of doing things. Hongkongers might look similar to other Chinese people, but they have their own language and culture that is different from the rest of China.
Some Hongkongers have been feeling upset and worried lately because they think that they're losing some of their special freedoms and rights that they've had for a long time. They worry that they might not be able to speak out against things they don't like, or that they might get in trouble for doing things they used to be able to do.
This has been going on for a while and some Hongkongers have been taking to the streets to protest and try to get their voices heard. They want to make sure that the people in charge know how they feel and that they want to keep their special freedoms and rights. It's kind of like if you and your friends want to make sure that the grown-ups don't take away your favorite toy or game - you would speak up and try to tell them how important it is to you.