Hi Zach,
I think it’s the linting stuff, and I’m just not seeing any of them. For instance, at about the 6:50 mark of 1.2.15 – Loops in JavaScript, where you are demonstrating an infinite loop, a warning pops up on js bin. That behaviour is shown in several videos in the series. None of them pop-up/display for me on jsbin using either Safari or Chrome. If that is linting, then on the https://jsbin.com/upgrade page, it states “…and many other features including preprocessors, linting and more.”
v