[Youtube] Fix "n" descrambling for player fae06c11

Resolves #30856.

youtube_dl/extractor/youtube.py

@@ -1464,15 +1464,15 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
     # 2. https://code.videolan.org/videolan/vlc/-/blob/4fb284e5af69aa9ac2100ccbdd3b88debec9987f/share/lua/playlist/youtube.lua#L116
     # 3. https://github.com/ytdl-org/youtube-dl/issues/30097#issuecomment-950157377
     def _extract_n_function_name(self, jscode):
-        target = r'(?P<nfunc>[a-zA-Z0-9$]{3})(?:\[(?P<idx>\d+)\])?'
+        target = r'(?P<nfunc>[a-zA-Z_$][\w$]*)(?:\[(?P<idx>\d+)\])?'
         nfunc_and_idx = self._search_regex(
-            r'\.get\("n"\)\)&&\(b=(%s)\([a-zA-Z0-9]\)' % (target, ),
+            r'\.get\("n"\)\)&&\(b=(%s)\([\w$]+\)' % (target, ),
             jscode, 'Initial JS player n function name')
         nfunc, idx = re.match(target, nfunc_and_idx).group('nfunc', 'idx')
         if not idx:
             return nfunc
         return self._parse_json(self._search_regex(
-            r'var %s\s*=\s*(\[.+?\]);' % (nfunc, ), jscode,
+            r'var %s\s*=\s*(\[.+?\]);' % (re.escape(nfunc), ), jscode,
             'Initial JS player n function list ({nfunc}[{idx}])'.format(**locals())), nfunc, transform_source=js_to_json)[int(idx)]
 
     def _extract_n_function(self, video_id, player_url):