Does anyone know how to create core packages? I want to add a custom title bar built in to atom but don’t know how to create core packages. Anyone know how to do this?
Core packages are packages bundled with atom. You would have to get the atom team to add it to their repo atom/atom. You are better off creating a community package in your own repo and publishing it to apm.
Check out the documentation how to create a community package.
Note core packages aren’t any more powerful than community ones. Bundling with the Atom install is basically the only difference.
Core packages may be more inclined to use private implementation details, because Atom can run the tests before a release and fix any broken packages, but there’s nothing stopping a community package from doing the same thing (other than risking breaking on every release).
But some Electron behaviours may not be possible to control in a package, perhaps this is what you meant by core. In this case, only a PR to Atom itself would work.