Feature Request: Ability to use "empty" default variable

[cpt-kuesel]

Using my new overlays.yml (https://gist.github.com/cpt-kuesel/ecc370016163fbf2db327f1c5b142749) as example again, I want to be able to use an empty default variable.

In the template overlays i define every language on my plex once as optional variable "language" and once as default variable "language_not".
With that my plex search can search for one language (optional variable) while excluding all other languages (default variables). but if i make a collection for english, english_not is automatically added and i need to overwrite it.
today i just use "de" as a quick fix for all non german collections, "en" for the german one.

but with this feature implemented i like to overwrite the language_not default variable as "empty", i think you suggested "None" in a thread on discord, so that the collection builder doesn't exclude "de" twice for my collections.