This is the debug world from java brought to bedrock edition so you can have fun with it or do a unique skyblock or find the perfect block to build with. This is the world used to test block types. Also, note that the whole overworld is the plains biome. Normally this would be gotten by clicking through the world options while holding shift but this is unable to be done normally in bedrock. This is the original debug world only put through a world converter.
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Changelog
Made it an mcworld file not sure why you wanted like this as they work less often but ok