DEBCONF_FRONTEND and DEBIAN_FRONTEND

["Thomas Gebhardt" <gebhardt@HRZ.Uni-Marburg.DE>]

Hi,

I am somewhat puzzled about the relationship between the two
env variables DEBCONF_FRONTEND and DEBIAN_FRONTEND.

The usersguide from the debconf docs says:

...
you  can  set  the DEBCONF_FRONTEND environment variable to the name of the
frontend to use. For example:
...  

On the other side /usr/lib/perl5/Debian/DebConf/Config.pm uses
the variable DEBIAN_FRONTEND:

...
If DEBIAN_FRONTEND is set in the environment, it overrides all this.
...

Are these actually the same variables (and there is a typo in the docs?)
If not, what is the difference?

Thanks, Thomas