I was inspecting the lodash tarball in npm registry, downloaded through npm pack lodash command, and was comparing the file contents with the files on the lodash GitHub repository. The tarball contains js files prefixed with an underscore that are not present in the repository. For example, _DataView.js, _coreJsData.js etc. There are 306 such files in the tarball that are not present in the repository.

Therefore, my question is,

(1) What are these files that are present in the npm tarball but not in the source repository?

(2) If they are auto-generated files, how to detect such files?