Recently, the Twenty Nineteen theme had been moved from Github to Trac. As Twenty Nineteen is the first core theme that uses npm and therefore contains a node_modules folder, runningĀ grunt
resulted in an error. I just created a minor patch, to solve this issue, and to make WordPress yet a little bit better. š
The Trac ticket can be found on Ignore theme based node_modulesĀ and my patch can be viewed via 46099.diff.