Amazon's affordable and feature-rich Fire TV Stick 4K has learned a new trick: the little streamer now supports display mirroring through Miracast. An update to Fire OS version 188.8.131.52 includes the new functionality, and it's rolling out now.
Early Fire TV hardware had Miracast functionality built in, but it was dropped some time ago. It's not likely many users noticed; the standard isn't nearly as ubiquitous as others like Chromecast. Still, some of Amazon's own Fire tablets can share their screen using Miracast, as well as many Windows PCs.
If you've got an updated Fire TV Stick 4K, you can initiate screen mirroring by holding the remote's home button to access the shortcut menu, then selecting Mirroring. The rest of the process takes place on the device whose screen you want to mirror.