/usr/lib/nodejs/es6-shim/es6-shim.map is in node-es6-shim 0.35.3+ds-1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/nodejs/es6-shim/../../../share/javascript/es6-shim/es6-shim.map
/usr/lib/nodejs/es6-shim/../../../share/javascript/es6-shim/es6-shim.map