diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index 05dcf8f96..12d6ecc35 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -368,6 +368,7 @@ class YoutubeIE(YoutubeBaseInfoExtractor):
                             (?:www\.)?hooktube\.com/|
                             (?:www\.)?yourepeat\.com/|
                             tube\.majestyc\.net/|
+                            # Invidious instances taken from https://github.com/omarroth/invidious/wiki/Invidious-Instances
                             (?:(?:www|dev)\.)?invidio\.us/|
                             (?:(?:www|no)\.)?invidiou\.sh/|
                             (?:(?:www|fi|de)\.)?invidious\.snopyta\.org/|