After researching this a bit more, I have found one major difference between map and path. I'm not sure if the Magento core team makes deliberate use of this, but per this Stack Overflow answer when you're define a map configuration, you're actually defining a prefix for mappings. i.e. Not only will this
map: {
'*': {
editTrigger: 'mage/edit-trigger',
}
}
ensure the loading the editTrigger module actually loads the mage/edit-trigger module, but also that editTrigger/foo would load the mage/edit-trigger/foo module.
The paths directive is not a prefix mapping. It's a simple one-to-one mapping.
The Magento_Ui/js/lib/ko/initialize library is, indeed, where Magento initializes its Knockout instance. Magento does not assign a ViewModel when it applies bindings.
The missing key here is the custom KnockoutJS binding named scope.
When Magento's Knockout instance encounters a scope: binding like this
<li class="greet welcome" data-bind="scope: 'customer'">
<span data-bind="text: customer().fullname ? $t('Welcome, %1!').replace('%1', customer().fullname) : 'Default welcome msg!'"></span>
</li>
It takes the value of that binding (named customer), and uses it to load and apply a ViewModel for the inner nodes from the uiRegistry. You can debug the data bound for a particular scope with some simple KnockoutJS pre debugging
<div data-bind="scope: 'someScope'">
<pre data-bind="text: ko.toJSON($data, null, 2)"></pre>
</div>
The uiRegistry is a simple dictionary like object, implemented in the Magento_Ui/js/lib/registry/registry RequireJS module.
vendor/magento/module-ui/view/base/requirejs-config.js
17: uiRegistry: 'Magento_Ui/js/lib/registry/registry',
Objects are put into the registry via the bits of javascript that look like this
<script type="text/x-magento-init">
{
"*": {
"Magento_Ui/js/core/app": {
"components": {
"customer": {
"component": "Magento_Customer/js/view/customer",
"extra_data_1":"some_value",
"more_extra":"some_other_value",
}
}
}
}
}
</script>
The program in the Magento_Ui/js/core/app module will examine the components key of the passed in object, and for each sub-object will
Fetch the object returned by the specified RequireJS module from the component key (Magento_Customer/js/view/customer)
Use that object to instantiate a new javascript object (see below)
Assign any extra data keys to that same object
Add that same object to the uiRegistry with the key of the original object (customer above)
If you're not sure how the x-magento-init script works, I've written an article about it here.
There's a more in depth examination of the app.js process over in this answer.
The implementation of the scope binding is defined here
vendor/magento//module-ui/view/base/web/js/lib/ko/bind/scope.js
Best Answer
RequireJS has a feature that allows you to set a custom baseUrl.
Magento generates baseUrl for RequireJS in the body of the page, where JS resources are requested. So, it's basically one more part of RequireJS config generated by Magento. This baseUrl is calculated on server side and is based on current theme, locale and base URL for static view files for the store. Then native RequireJS functionality calculates full path as follows