How to make another context (not "web") set by default?

/* Initialize the default 'web' context */
$modx->initialize('web');

// to
/* Initialize the default 'yourcontext' context */
$modx->initialize('yourcontext');

if ( $modx->context->get('key') != 'mgr' ) {
	/* grab the current language from the cultureKey request var */
	$ckey = $_REQUEST['cultureKey'];
	$host = strtolower(MODX_HTTP_HOST);
	switch (true) {
		case $ckey == 'de':
			/* switch the context */
			$modx->switchContext('web');
			break;
		case $ckey == 'fr':
			/* switch the context */
			$modx->switchContext('fr');
			break;
		default:
			/* Set the default context here */
			$modx->switchContext('defaultcontext');
			break;
	}
	/* unset GET var to avoid
	 * appending cultureKey=xy to URLs by other components */
	unset($_GET['cultureKey']);
}

// + some .htaccess rule like
<IfModule mod_rewrite.c>
	# favicon redirect
	RewriteCond %{REQUEST_FILENAME} !-d
	RewriteCond %{REQUEST_FILENAME} !-f
	RewriteRule ^(de|fr)/favicon.ico$ favicon.ico [L,QSA]

	# assets/* redirect
	RewriteCond %{REQUEST_FILENAME} !-d
	RewriteCond %{REQUEST_FILENAME} !-f
	RewriteRule ^(de|fr)/assets(.*)$ assets$2 [L,QSA]
	 
	# everything else redirect and setting cultureKey
	RewriteCond %{REQUEST_FILENAME} !-f
	RewriteCond %{REQUEST_FILENAME} !-d
	RewriteRule ^(de|fr)?/?(.*)$ index.php?cultureKey=$1&q=$2 [L,QSA]
</IfModule>