Chris Dias, writing at the Visual Studio Code blog:

Thanks for all the passionate feedback. It has been very helpful, painful, and entertaining all at the same time. We’re changing the orange icon to blue for Stable and keeping green for Insiders.

[…]

For complete transparency, we want to share some history as we think it helps to understand how we arrived at orange in the first place.

This whole piece is a great read. I’d always thought the original blue VS Code icon was horrendously ugly. Chris explains why here — it’s because, “It was really meant to be a favicon.” Makes total sense. In contrast, the newest blue icon is by far the best looking rendition the company’s done. It’s one of the many reasons that VS Code is the IDE I currently use for everything.

This part scares me though:

We are exploring using a non-tilted icon for macOS based on @donysukardi’s comment here. We can’t say yet that we’ll do this, but we are going to explore it and either way, we’ll post updates in that issue.

I’m with jeffbox on this one, who “much prefers” the tilted version.