The component uses a render method to pass down, into the default slot, the things we need. To access that stuff, we use a template element and v-slot to extract this.
That is essentially what a renderless component is. Rather than output the greeting in the component, we're exposing it, and leaving up to the implementation to decide how that data or functionality gets used.
A toggle renderless component
Here's the renderless component for the toggle functionality we saw above.
If you were initially confused by the myriad examples around renderless components, I hope this has cleared up your confusion.
There is a lot more you can do with renderless components depending on the complexity of what you're building, but this wasn't intended to cover that – my goal was to explain as simply as possible what renderless components are.