function onExists( error, bool ) { // eslint-disable-line no-unused-vars
			if ( error ) {
				debug( 'Encountered an error when searching for a README. Directory: %s (%d of %d). Error: %s', dir, i+1, total, error.message );
			} else {
				debug( 'Found a package README.' );
				out.push( fpath );
			}
			done();
		}
Callback invoked after checking for a README.

@private
@param {(Error|null)} error - error object
@param {boolean} bool - boolean indicating if a file exists