Sigma Rebase is built using the actual 1.16.4 MCP, while Sigma Remap can be harder to read. (Sigma Rebase is currently in development)
1.Clone this repo and open it in intellij;
2.Set up the project (libraries, natives);
3.Open the project structure with Ctrl + Alt + Shift + S;
4.Find and click on the Artifacts tab;
5.Press + -> JAR -> Empty;
6.In the Available Elements tab, right-click on Libraries -> Extract into Output Root;
7.In the same tab, right-click on your compile output icon -> Put into Output Root
8.Give your artifact a name (optional);
9.Close the project structure window and find the Build tab -> Build artifacts and double-click on your created artifact; This jar will be then compiled in your project's directory/out/artifacts/artifact name/artifact name.jar