YouTube Theatre Mode is a free add-on for Chrome that enhances the standard YouTube theatre experience. This extension modifies the default layout, allowing the video player to occupy the entire browser window for a more immersive viewing experience. The design aims to replicate the theatre mode familiar to Twitch users, providing a seamless transition for those accustomed to that platform.

In addition to the improved video display, the extension features the inclusion of a chatroom for livestreams, which remains visible unless closed by the user. This functionality enhances interactivity during live events, making it easier for viewers to engage with the content and each other in a more theatre-like environment.