It's a (anti-)fire grenade. These used to be very common up until the 1930s. It's filled with an anti-fire chemical of some kind. Historically they used some sort of toxic chemical but modern ones sometimes produce CO2 or ammonia to smother the fire. Some historical ones had gunpowder in them to spread the the anti-fire chemical better. They were replaced by squirting fire extinguishers because those turned out to just be better.

Here's a video by some nerd: https://www.youtube.com/watch?v=iNhjfk9BTNA

Edit: It looks like these recalled fire grenades also contain a gunpowder charge. So they explode into anti-fire powder.

Do you yeet it into the fire??? Like what am I seeing here? Lol