Yes, if the video was uploaded in that quality. The list shows every quality YouTube has for the video, with HDR and 60 fps when the video has them, and the size of each file before you download.
Choose an option under Audio. M4A and Opus are saved exactly as YouTube provides them, without re-encoding. MP3 is made from that sound at 320 kbit/s.
Paste the playlist link and the list of its videos opens. Any video from it can be downloaded on its own. With Plus you can download the whole playlist or several videos at once, up to 7 at a time.
Yes. Under the list of formats, open Subtitles, cover, description. Subtitles are saved as SRT: every track the author uploaded, and auto-generated ones in the video's language and in English. Auto-generated ones are marked. The cover is the video's picture in the best quality as JPG, the description is a TXT file with the title, the channel and the link.
Private videos, videos for channel members or YouTube Premium subscribers, paid and copy-protected (DRM) films, and live streams while they are on air or just after they end. Some videos are available only in certain countries, and the site may not be able to get them.
No. Downloading works without signing in, on a phone or a computer. A ready file is kept for 24 hours and then deleted.