Alright. I wanted to verify something to double check. Here is the flow of how my comment gets to your instance and is visible by you. It helps when you realize that all communications you do are with your instance. I might get inbox/outbox terminology reversed or wrong.

1. I post a comment to !fediverse@lemmy.world, but it is done through programming.dev/c/fediverse@lemmy.world. this goes to programming.dev’s inbox.
2. Because lemmy.world is federated with programming.dev, they scoop up my comment from programming.dev’s outbox
3. Because jlau.lu is federated with lemmy.world, they get my comment from lemmy.world.
4. When you view !fediverse@lemmy.world through jlau.lu/c/fediverse@lemmy.world you will see my comment from your server’s copy of it.

I say the canonical copy is on my home instance because imagine a scenario where lemmy.world is NOT federated with programming.dev but for whatever reason programming.dev didn’t defederate back. I could still see and comment on !fediverse@lemmy.world. Other users of programming.dev could see my comments and reply, but nobody else.

This is how I understand federation to work but it might be incorrect. It’s a complicated topic. It might be that your instance directly gets the comment from mine.