[extractor/bbc] Support onion domains (#5211)

Authored by: DoubleCouponDay

yt_dlp/extractor/bbc.py

@@ -591,7 +591,12 @@ def _real_extract(self, url):
 class BBCIE(BBCCoUkIE):
     IE_NAME = 'bbc'
     IE_DESC = 'BBC'
-    _VALID_URL = r'https?://(?:www\.)?bbc\.(?:com|co\.uk)/(?:[^/]+/)+(?P<id>[^/#?]+)'
+    _VALID_URL = r'''(?x)
+        https?://(?:www\.)?(?:
+            bbc\.(?:com|co\.uk)|
+            bbcnewsd73hkzno2ini43t4gblxvycyac5aw4gnv7t2rccijh7745uqd\.onion|
+            bbcweb3hytmzhn5d532owbu6oqadra5z3ar726vq5kgwwn6aucdccrad\.onion
+        )/(?:[^/]+/)+(?P<id>[^/#?]+)'''
 
     _MEDIA_SETS = [
         'pc',
@@ -841,6 +846,12 @@ class BBCIE(BBCCoUkIE):
             'upload_date': '20190604',
             'categories': ['Psychology'],
         },
+    }, {  # onion routes
+        'url': 'https://www.bbcnewsd73hkzno2ini43t4gblxvycyac5aw4gnv7t2rccijh7745uqd.onion/news/av/world-europe-63208576',
+        'only_matching': True,
+    }, {
+        'url': 'https://www.bbcweb3hytmzhn5d532owbu6oqadra5z3ar726vq5kgwwn6aucdccrad.onion/sport/av/football/63195681',
+        'only_matching': True,
     }]
 
     @classmethod