Whats easiest way to get mojang mapped minecraft client + server 'source'? (Including parameter names)
should be able to specify 1.20.5 or 1.20.6 or latest snapshot and it should be able to run client from it, currently I am using MCP reborn, but it takes a while to update when minecraft updates

This is not related to Fabric API at all.

Use Parchment mappings to get parameter names.

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