mediawiki/skins/Nimbus does not pass jshint. It should provides a default .jshintrc file (probably just containing: {}. And the error have to be fixed:
nimbus/Menu.js: line 62, col 19, 'e' is already defined.
nimbus/Menu.js: line 133, col 19, 'e' is already defined.
nimbus/Menu.js: line 155, col 39, 'source_id' is already defined.
nimbus/Menu.js: line 161, col 35, 'source_id' is already defined.
nimbus/Menu.js: line 172, col 19, 'e' is already defined.
nimbus/Menu.js: line 194, col 19, 'e' is already defined.
nimbus/Menu.js: line 215, col 19, 'e' is already defined.
Version: unspecified
Severity: normal