add_filter('post_rewrite_rules', array($this,'filter_post_rewrite_rules') );
add_filter('page_rewrite_rules', array($this,'filter_page_rewrite_rules') );
// var_dump there the first arg.
also:

										add_filter( 'request',  function  ( $query_vars ) {
											if(!is_admin()) {
												echo '<pre>' . print_r( $query_vars, true ) . '</pre>';
											}
											return $query_vars;
										} , 1 );



Posts (original)
array (size=19)
  '[^/]+/attachment/([^/]+)/?$' => string 'index.php?attachment=$matches[1]' (length=32)
  '[^/]+/attachment/([^/]+)/trackback/?$' => string 'index.php?attachment=$matches[1]&tb=1' (length=37)
  '[^/]+/attachment/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?attachment=$matches[1]&feed=$matches[2]' (length=49)
  '[^/]+/attachment/([^/]+)/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?attachment=$matches[1]&feed=$matches[2]' (length=49)
  '[^/]+/attachment/([^/]+)/comment-page-([0-9]{1,})/?$' => string 'index.php?attachment=$matches[1]&cpage=$matches[2]' (length=50)
  '[^/]+/attachment/([^/]+)/embed/?$' => string 'index.php?attachment=$matches[1]&embed=true' (length=43)
  '([^/]+)/embed/?$' => string 'index.php?name=$matches[1]&embed=true' (length=37)
  '([^/]+)/trackback/?$' => string 'index.php?name=$matches[1]&tb=1' (length=31)
  '([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?name=$matches[1]&feed=$matches[2]' (length=43)
  '([^/]+)/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?name=$matches[1]&feed=$matches[2]' (length=43)
  '([^/]+)/page/?([0-9]{1,})/?$' => string 'index.php?name=$matches[1]&paged=$matches[2]' (length=44)
  '([^/]+)/comment-page-([0-9]{1,})/?$' => string 'index.php?name=$matches[1]&cpage=$matches[2]' (length=44)
  '([^/]+)(?:/([0-9]+))?/?$' => string 'index.php?name=$matches[1]&page=$matches[2]' (length=43)
  '[^/]+/([^/]+)/?$' => string 'index.php?attachment=$matches[1]' (length=32)
  '[^/]+/([^/]+)/trackback/?$' => string 'index.php?attachment=$matches[1]&tb=1' (length=37)
  '[^/]+/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?attachment=$matches[1]&feed=$matches[2]' (length=49)
  '[^/]+/([^/]+)/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?attachment=$matches[1]&feed=$matches[2]' (length=49)
  '[^/]+/([^/]+)/comment-page-([0-9]{1,})/?$' => string 'index.php?attachment=$matches[1]&cpage=$matches[2]' (length=50)
  '[^/]+/([^/]+)/embed/?$' => string 'index.php?attachment=$matches[1]&embed=true' (length=43)

Pages:
array (size=13)
  '.?.+?/attachment/([^/]+)/?$' => string 'index.php?attachment=$matches[1]' (length=32)
  '.?.+?/attachment/([^/]+)/trackback/?$' => string 'index.php?attachment=$matches[1]&tb=1' (length=37)
  '.?.+?/attachment/([^/]+)/feed/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?attachment=$matches[1]&feed=$matches[2]' (length=49)
  '.?.+?/attachment/([^/]+)/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?attachment=$matches[1]&feed=$matches[2]' (length=49)
  '.?.+?/attachment/([^/]+)/comment-page-([0-9]{1,})/?$' => string 'index.php?attachment=$matches[1]&cpage=$matches[2]' (length=50)
  '.?.+?/attachment/([^/]+)/embed/?$' => string 'index.php?attachment=$matches[1]&embed=true' (length=43)
  '(.?.+?)/embed/?$' => string 'index.php?pagename=$matches[1]&embed=true' (length=41)
  '(.?.+?)/trackback/?$' => string 'index.php?pagename=$matches[1]&tb=1' (length=35)
  '(.?.+?)/feed/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?pagename=$matches[1]&feed=$matches[2]' (length=47)
  '(.?.+?)/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?pagename=$matches[1]&feed=$matches[2]' (length=47)
  '(.?.+?)/page/?([0-9]{1,})/?$' => string 'index.php?pagename=$matches[1]&paged=$matches[2]' (length=48)
  '(.?.+?)/comment-page-([0-9]{1,})/?$' => string 'index.php?pagename=$matches[1]&cpage=$matches[2]' (length=48)
  '(.?.+?)(?:/([0-9]+))?/?$' => string 'index.php?pagename=$matches[1]&page=$matches[2]' (length=47)

Posts (customly registered)
array (size=6)
  '(.+?)/feed/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?post=$matches[1]&feed=$matches[2]' (length=43)
  '(.+?)/(feed|rdf|rss|rss2|atom)/?$' => string 'index.php?post=$matches[1]&feed=$matches[2]' (length=43)
  '(.+?)/embed/?$' => string 'index.php?post=$matches[1]&embed=true' (length=37)
  '(.+?)/page/?([0-9]{1,})/?$' => string 'index.php?post=$matches[1]&paged=$matches[2]' (length=44)
  '(.+?)/comment-page-([0-9]{1,})/?$' => string 'index.php?post=$matches[1]&cpage=$matches[2]' (length=44)
  '(.+?)/?$' => string 'index.php?post=$matches[1]' (length=26)