Most indoor cats enjoy looking out windows and are entertained when things are happening outside, but unless there's a birdfeeder outside the window or something else that draws activity, there's often not much to look at.
If you think of a TV or computer screen as a virtual window that your cat can watch and listen to then you can provide a constant source of activity that entertains your cat or sounds that soothe your cat. You can also easily switch what's being played to provide variety that a window can't offer.
Whether it's a passive watching experience for your cat, a more interactive chase experience, or a relaxing sound experience, there are a number of free YouTube videos available to provide that.
Below are a few dozen videos for you to try out with your cat to explore what kitty wants. If you want more then simply search YouTube or visit the YouTube channels of the videos. You can also show live feeds from YouTube of bird feeders for your cat to watch.
You can expand a video to full screen by clicking on the icon in the lower right-hand corner of the video once it's playing. Click on the YouTube icon on the bottom of the video to see it at the YouTube website and get additional information about the video and the channel link to find more videos from that channel.