Can youtube-dlp download youtube videos with the chapter descriptions like y2down.cc

What do you mean descriptions? Like the video's description body text? If so, yes. Gimme one moment to get on my computer, and I'll edit this comment to include the command args.

EDIT: This is the specific shell alias I use when I'm archiving videos for backup.

yt-archive() {
    yt-dlp --embed-chapters \
        --concurrent-fragments 5 \
        --restrict-filenames \
        --write-description \
        --write-subs \
        --write-auto-subs \
        --sub-langs="en.*" \
        --paths="~/Archival/" \
        "$@"
}

The command arg you're likely most interested in is --write-description which will output the text to a text file alongside the video file

--embed-metadata

Embed metadata to the video file. Also embeds chapters/infojson if present unless --no-embed-chapters/--no-embed-info-json are used (Alias: --add-metadata)

from the yt-dlp github page

It does fucking everything lol.

Thought it was just for YouTube videos until I got it recently and read the man file. The amount of shit you can do with it is insane.