QuickLook is an app that runs in the background and brings the macOS "quick look" feature to Windows anytime you press the space bar.
Anywhere you can access a file or folder, press the spacebar, and the window will pop up, giving you some basic information depending on the type of file. For example, Quick Look will provide you with the file or folder name, last modified, and size. Other options will again be available, depending on the file or folder you open. A good example is that an image file will have the "Open with Photos" option. Press the spacebar or the X in the top right to close the window.
Quick Look will not preview root folders but will preview any sub-folders. In this case, it can show you the last modified date and the number of files and folders within.
Plugins are also available to extend its functionality. We like this because it keeps the program from becoming bloated by not overdoing it with many features you don't need. Quick Look uses no CPU when idle and around 25 MB during our testing. When executed, the memory usage is almost the same, and expect 4-12% CPU usage while getting the information.
QuickLook is perfect for Mac users who also need to use Windows and miss this feature. Windows users have always enjoyed seeing some of the Mac features as well.