This is my guess as well. But I doubt anyone would be writing their code like "${userId}-${otherPart}" so copilot itself noticed that in all codebases with hard

This is my guess as well. But I doubt anyone would be writing their code like "${userId}-${otherPart}" so copilot itself noticed that in all codebases with hardcoded twitter keys(which shouldn't be common on github I think) that their is a partial match and this is a useful information(given that in such a large corpus of all public github code partial matches would be quite common and ratio of signal to noise should be less). Whatever the case, I started as a skeptic thinking this is pure gimmick and now each day I am impressed by something new that copilot can do.