These are all cookies primarily used by YouTube (Google) to manage user experience, track analytics, and handle privacy preferences, particularly when embedded videos are present on a website.
Here is a breakdown of each cookie:

__Secure-ROLLOUT_TOKEN: Used by YouTube to manage the phased rollout of new features and experiments. It assigns users to specific test groups for UI changes or new functionalities, with a 6-month lifespan. The __Secure- prefix indicates it is only transmitted over HTTPS.
VISITOR_INFO1_LIVE: A YouTube cookie used to estimate user bandwidth on pages with embedded videos. It may also be used to enable personalized recommendations based on past views. It generally lasts for 6 months.
VISITOR_PRIVACY_METADATA: Stores a user's consent and privacy choices regarding, for example, personalized ads or tracking, specifically for embedded YouTube content.
YSC: A session cookie set by the YouTube video service on pages with embedded video, used to track views and manage user interaction with the video player. It expires at the end of the browser session.

The __Secure-YEC cookie is a security and functionality cookie set by YouTube, typically with a 13-month lifespan, designed to detect bot traffic and prevent fraud. It is used to enhance security by ensuring valid user sessions, especially when interacting with embedded YouTube video players.

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