Screenshot from a Meteor app I designed, built, and formerly maintained at spritebuilder.com for for marketing and distributing SpriteBuilder, an open-source macOS game creation toolkit. I wasn't involved in the design of the app itself (the screenshot within the screenshot).
Write-up in progress…
In the meantime, visit spritebuilder.com, which still is running the webapp I designed and built as of this writing (July 2017), though I no longer maintain it. Then come back later, or tweet at me for more details about this project.