Copilot is essentially AI autocomplete for programming. It is a little bit of software you install alongside your editor that has been trained on billions of lines of code across dozens of languages.
In the few weeks I've been using it, it has already saved me literally hours of work. I will be signing up and paying for it, but for now I've still got some time to run on the free three month trial.
Github Copilot appeared in Issue 9 in the Useful section.