How to get RSS feed of YouTube Channels, Users and Playlists

Taking user and channel IDs can be found on link URL of a user and a channel like:

https://www.youtube.com/user/{USER_ID_STRING} https://www.youtube.com/channel/{CHANNEL_ID_STRING}

then you can apply this ID string into the RSS feed URL like:

https://www.youtube.com/feeds/videos.xml?user={USER_ID_STRING}https://www.youtube.com/feeds/videos.xml?channel_id={CAHNNEL_ID_STRING} 

You can get playlist ID by the link URL of the playlist, something like that

https://www.youtube.com/playlist?list={ID_STRING}&playnext=1&index=1

then use this ID into your RSS URL

https://www.youtube.com/feeds/videos.xml?playlist_id={PLAYLIST_ID}

Cool, right?