This feature is now in general availability as of version 4.3.0
https://community.passbolt.com/t/new-release-v4-3-0-no-one-knows/8520
The caveats being
- You can only create/edit the TOTP on the mobile app, not in a browser
- Once you add TOTP to a credential, you can no longer edit it using the browser, all edits must be done in the mobile app
- Since you can’t edit the description field on the mobile app, once you add a TOTP to a credential, you can no longer edit the description on any client.
And here’s a demo of it : https://www.youtube.com/watch?v=C4Ef10jkHkQ&t=248s