In the left gutter of the editor view for an Xcode Playground page, you see a stripe/ribbon that tracks the hovering cursor. Questions: What is this called? In what way is it useful? So useful it's compulsory, or how can I turn it off? After clicking Execute Playground I would like the playground to execute. How do I go about this? Xcode help and documentation, nothing; DuckDuckGo, nothing, just the good news of publishing apps from your iPad, then child recreation. I saw it used in a WWDC23 session, but I didn't catch any remark on it. My mind does wander; but… if it's wandered so far as to wipe it from the web, then the ghost of Philip K. **** walks among us. If I am working on line 42 out of 170, and I want to see it execute it in the context of the whole page, I must first scroll to the bottom, click the blue circle, and ⌘Z / ⇧⌘Z to get back to what I was working on. Is this correct? Maybe if I stopped worrying and learned to love the strip, I'd appreciate it, but not yet. Please tell me how to be happy with the ergonomics. Off-topic… :… because every search result from the web and Apple documentation is about these: Xcode Playground Singular, not "Playgrounds" No "app" in the name.