Firefox plugin does not support HTTP BasicAuth

When entering a server URL as

https://myuser:mypassword@myltserver/v2

in Firefox plugin → Advanced settings → Other server
It does not work.

But the url provide expected error message from LT server when used with Firefox or curl, and it works when I remove authentication from the reverse proxy (traefik).

It sounds like a bug.
Having 2 extra fields for username & password would be even better.