Earlier quoted context omitted.
> YouTube used to have a freely accessible search API. Twitter used to have RSS/Atom feeds for each account so you could follow someone without a client, just a regular old news aggregator.
AFAIK they still do, just without any way to find it except by digging into the channel page’s HTML to find the channel_id and then constructing the feed URL from that (“ https://www.youtube.com/feeds/videos.xml?channel_id=$channel... ) — or (edit) using something like https://github.com/rss-bridge/rss-bridge that presumably does something like that under the hood — so I guess scraping for an undocumented API.
Personally, for channels, I use a script only needs to access the channel's page; it outputs a list of all the videos in the channel. One of the more recent web development trends I dislike are sites that "load more results" using additional Javascript-triggered HTTP requests in response to scrolling a page. YouTube channels with multiple pages of videos are one example.
With custom scripts I wrote for searching YouTube, outputting lists of videos from channels, and downloading non-commercial videos, I can use YouTube without the need a graphical browser.