Bedrock Developer Beta

Bedrock Edition Dev is a developer beta version of Multiple Bedrock Versions accessible only by developers and marketplace content creators. It was discovered and leaked by multiple sources and was showcased by a YouTuber named Element X.

He also leaked the 1.18 Developer edition which included the unreleased fireflies and bundles. However, he received an email from Mojang associates asking him to take down his video and threatening legal action against him.

Mojang is infamous for falsely striking videos showcasing the developer editions, and even authorizing Marketplace Partners to falsely strike videos that just mention Minecraft Developer Edition.

The existence of the versions were also spread by a user known as TantalusC. He had gotten many copyright claims by Mojang/Mojang enforcement, ranging from "Pirated Marketplace Assets" to being claimed for a song Mojang didn't own.

There hasn't been much documentation on Minecraft Developer Edition.

Differences from public beta versions
This version has additional development features, for example: an F3 screen, advanced developer settings for terrain generation and weather, and the ability to slow down the time without needing an add-on. Another feature is the viewing of hitboxes, and even various graphs.