FFplay is part of the FFmpeg suite, it's the application dedicated to viewing media files. Since it's based on the same libraries it still maintains most of the features of FFmpeg itself and can give some informations on the media being played (although the application for that is FFprobe).
Note: FFmpeg can play the video stream using video outputs, for example with

ffmpeg -re -i file.mp4 -f sdl2 -

although outputs usually have limited pixel formats.