Yes, the official plugin sends context from recently opened other buffers. It determines what context to send by computing a jaccard similarity score locally. I

Yes, the official plugin sends context from recently opened other buffers. It determines what context to send by computing a jaccard similarity score locally. It uses a local 14-dimensional logistic regression model as well for some decisions about when to make a completion request, and what to include. There are some reverse-engineering teardowns that show this.