"Undefined" when trying to use Soy template?

Unfortunately no, that doesn’t help.
Something I noted tough:
When looking at the script in the dev console something like this should be given at the start:

;/* module-key = 'com.comsysto.kitchen-duty-plugin:kitchen-duty-plugin-resources--planning-page', location = 'templates-soy/kitchen-duty-planning.soy' */
// This file was automatically generated from kitchen-duty-planning.soy.
// Please don't edit this file by hand.

/**
 * @fileoverview Templates in namespace JIRA.Templates.KDP.
 */

The example above is from a working version according to that tutorial here: Redirecting ...

However, the view I’m having just starts like this:

;/* module-key = 'com.scholledev.jira-wfenhance:library-management-resource-module', location = 'js/responsible-user-search.js' */
var showSuccessFlag = function(a) {
    require(["aui/flag"], function(c) {
        var b = c({