Great news for those who weren't already aware through GitHub or Discord!
This has now been added as an official widgets system for ENIGMA, and therefore, the extension is no longer needed to be downloaded or installed. You can now use all the same functions on Linux and Mac by simply updating ENIGMA and removing the *_tfd suffix from all of your function names that have that suffix. Bug fixes have also been applied, such as support for double quotes in your strings.
But do note Zenity still needs to be installed on both your Linux machine, as well as those who download your game for Linux, as normal.