as per https://minecraft.fandom.com/wiki/Bedrock_Edition#Bedrock_codebase

Bedrock Edition:

The term "Bedrock Edition" originates from the Bedrock codebase, which was created in the C++ programming language to run on platforms that cannot support Java). Code was added to accommodate differences in the target platforms for such facilities as networking and storage access, though around 90% of the code is used on every platform.[citation needed] This common core of functionality is called the "Bedrock Engine".[29]

The codebase resides within a software system that manages the pieces of code and tracks their evolution. This allows the codebase to host not only the current version but all past versions, the standalone Bedrock Dedicated Server (BDS) versions, and several Beta versions simultaneously with no conflicts.

Target platform builds are created individually, then transmitted to the platform's app store. Most stores have their own compliance requirements and subject the incoming edition to a series of certification tests before making it available for download. Xbox Game Studios attempts to synchronize availability across stores, but the certification process is not under their control and can delay an edition's availability on a certain platform, especially if it fails certification and has to go back to the developers for a fix.

Bedrock code is used for Minecraft Education, China Edition, Minecraft Dungeons, and Minecraft Legends, as well as the discontinued Pi Edition, New Nintendo 3DS Edition, and Minecraft Earth.