What is a community note?
I Googled it:
“Community Notes aim to create a better informed world by empowering people on X to collaboratively add context to potentially misleading posts. Contributors can leave notes on any post and if enough contributors from different points of view rate that note as helpful, the note will be publicly shown on a post. Sign up to become a contributor.
Community Notes are now publicly visible to everyone in the US. For more information, we have included responses to frequently asked questions below, but you can learn more through the Community Notes Guide as well. “