TOTP is a tool for the BBC Master to generate authentication codes to login to GitHub.
During the GitHub process to enable two-factor authentication it will ask you to scan a barcode. Instead, click the "enter this code instead" link. The code is a short string of letters and numbers.
Run the TOTP app in beebem or on your Master by using SHIFT+BREAK or by
running *TOTP. It will prompt you for the key. It will then display an
authentication code. For example:
>*TOTP
Enter key (it will be saved):
ABCDEFGHABCDEFGH
772479
The next time you run the tool it will use the saved key and display a new code based on the current time.
For this to work the real-time clock must be set correctly.
The Master clock is usually set to local time but the calculation requires UTC. A workaround is to set the clock to UTC. The fix is add a configurable time zone offset. Or a separate TOTPBST command!
If this seems to be generating bogus codes use another tool, for example 2fa.
You can recover the original key by running *TYPE STORE on your Master.