That's the password to the email sever thunderbird connects to. Thunderbird by itself does nothing until the user setups the email POP3/IMAP setup to retrive the emails.

OK. Where does one locate " email POP3/IMAP setup to retrive the emails."

I asked the question last week, but got no reply. Does user markwarner22 not know the answer to acting on his own advice?

Thunderbird does not have a password nor does it offer accounts.

Passwords are associated with your email address, something@some.domain. If you no longer remember your email password then you must go to the website https://some.domain/ and go through the process defined there of having your password changed or reset.