FWIW, the workaround from
https://github.com/mps-youtube/mps-youtube/issues/565
fixed it for me:
--- /tmp/backend_youtube_dl.py 2018-05-28 15:38:51.447473367 +0200
+++ /usr/lib/python3/dist-packages/pafy/backend_youtube_dl.py 2018-05-28
15:36:25.649637288 +0200
@@ -50,7 +50,9 @@
self._likes = self._ydl_info['like_count']
self._dislikes = self._ydl_info['dislike_count']
self._username = self._ydl_info['uploader_id']
- self._category = self._ydl_info['categories'][0]
+ # self._category = self._ydl_info['categories'][0]
+ #
https://github.com/mps-youtube/mps-youtube/issues/565#issuecomment-384835223
+ self._category = '565'
self._bigthumb = g.urls['bigthumb'] % self.videoid
self._bigthumbhd = g.urls['bigthumbhd'] % self.videoid
self.expiry = time.time() + g.lifespan
