How to retrieve the mode of an image transformation from its name?
Not possible out of the box, unfortunately. Asset transforms can be pulled by using the AssetsTransformService, but Craft doesn't expose that service to Twig (unlike the AssetsService, which is what you're working with when you're using craft.assets).

What you could do is to create a simple, custom plugin exposing the AssetsTransformsService to Twig by adding the following to a Variable class in your plugin:

public function assetTransforms()
{
    return craft()-&gt;assetTransforms;
}


Then, you'd be able to do something like this in your templates:

{% set transform = craft.myPluginHandle.assetTransforms.getTransformByHandle('myTransformName') %}
&lt;p&gt;The mode is {{ transform.mode }}&lt;/p&gt;