When you build solutions for SharePoint, you will inevitably run into scenarios where you need some sort of data and content. This might be a situation where you are creating a web part that lists news items that are saved in a SharePoint list. Or this might be a scenario where you'll show the latest modified documents, and based on that, provide additional information for users. In most scenarios, you'll find it more helpful if you have data and content within SharePoint that you can access, view, and use.
With previous development models for SharePoint, it was customary to mock up data. This could be garbage, or classic lorem ipsum content scattered around to help a developer mimic a real-world service when developing, testing, and troubleshooting code. For, on-premises SharePoint (and to a certain degree SharePoint Online), there have been several tools that generate content that looks and acts real.
You might still, at times, need...