function findREADMEs() {
	var options;
	var gopts;
	var opts;
	var clbk;
	var err;
	var dir;

	opts = copy( config );
	if ( arguments.length < 2 ) {
		clbk = arguments[ 0 ];
	} else {
		options = arguments[ 0 ];
		clbk = arguments[ 1 ];
		err = validate( opts, options );
		if ( err ) {
			throw err;
		}
	}
	if ( !isFunction( clbk ) ) {
		throw new TypeError( format( 'invalid argument. Callback argument must be a function. Value: `%s`.', clbk ) );
	}
	if ( opts.dir ) {
		dir = resolve( cwd(), opts.dir );
	} else {
		dir = cwd();
	}
	// Find `package.json` files...
	gopts = {
		'cwd': dir,
		'ignore': opts.ignore,
		'realpath': true // return absolute file paths
	};
	glob( opts.pattern, gopts, onGlob );

	/**
	* Callback invoked after matching files.
	*
	* @private
	* @param {(Error|null)} error - error object
	* @param {(EmptyArray|StringArray)} files - list of matching files
	* @returns {void}
	*/
	function onGlob( error, files ) {
		if ( error ) {
			return done( error );
		}
		if ( files.length ) {
			return find( files, done );
		}
		return done( null, [] );
	}

	/**
	* Callback invoked upon finding READMEs.
	*
	* @private
	* @param {(Error|null)} error - error object
	* @param {(EmptyArray|StringArray)} files - files
	* @returns {void}
	*/
	function done( error, files ) {
		if ( error ) {
			return clbk( error );
		}
		clbk( null, files );
	}
}
Asynchronously finds package READMEs.

@param {Options} [options] - function options
@param {string} [options.dir] - root directory from which to search for package READMEs
@param {string} [options.pattern='**\/package.json'] - glob pattern
@param {StringArray} [options.ignore] - glob pattern(s) to exclude matches
@param {Callback} clbk - callback to invoke after finding package READMEs
@throws {TypeError} callback argument must be a function
@throws {TypeError} options argument must be an object
@throws {TypeError} must provide valid options
@throws {Error} `pattern` option must end with `package.json`

@example
findREADMEs( clbk );

function clbk( error, files ) {
    if ( error ) {
        throw error;
    }
    console.dir( files );
}