What is sender variable represent in all of the channel

Studio
1

As far as i know,

{{{sender}}} in Whatsapp is the phone no and it will be the same across the bot.

i have question what is sender

  1. Sender in Facebook
    a, Is the sender for 1 facebook account is always same in the bot or depends on session?
    b. Is the sender for 1 facebook account is always same across the different bot? if different, how we can get the profile id?

  2. Sender in Instagram
    a, Is the sender for 1 Intagram account is always same in the bot or depends on session?
    b. Is the sender for 1 facebook account is always same across different bot if different, how we can get the profile id?

  3. Sender in Website if we don not pass ymAuth.
    a. What is sender in website? how long the same sender in website will still be the same?