How can I add a comment (for developers, not in output HTML) to an Angular template?

Angular doesn't have template comment support built in. You could, however, create a comment directive to support it, like this.

app.directive('templateComment', function () {
    return {
        restrict: 'E',
        compile: function (tElement, attrs) {
            tElement.remove();
        }
    };
});

Markup would then be:

<template-comment>Put your comment here.</template-comment>

Alternately, you could use standard html comments, and then strip them out of your production code before deployment.

Consider this grunt task, if you'd like to support block comments - https://github.com/philipwalton/grunt-strip-code Specify a start comment and an end comment, and your comment block will be stripped out of the production code, assuming your add this task to your deploy target. Use it as a model for you build process, if you're not using Grunt. ....

You can use normal syntax for comments without special symbols like <!-- Order verification, and authorization -->, then you can minify html (grunt + htmlmin)

htmlmin: {
      dist: {
        options: {
          collapseWhitespace: true,
          collapseBooleanAttributes: true,
          removeCommentsFromCDATA: true,
          removeOptionalTags: true,
          removeComments: true,
          ignoreCustomComments: [ /[<>\:\[\]\#]+/ ]

        },
        files: [{
          expand: true,
          cwd: '<%= yeoman.dist %>',
          src: ['*.html', 'views/**/*.html'],
          dest: '<%= yeoman.dist %>'
        }]
      }
    },