Question: For example, if you have thousands of colors (options) in the `color` attribute, it becomes a pain to use the drag & drop sorting functionality.

I'd like to override the default sorting (based on option `position`) to sort by `attribute label` alphabetically for all attributes.

I did some digging around in core files, but couldn't locate the class or function which does this.

Any ideas where this functionality is inside Magento's core?

Answer: 
you can download this module <https://github.com/nhutnguyenvu/alphabet-option>. It allows you can sort any attributes by alphabet (desc, asc) or position
So I have had a development done to make the usability of product attributes with "many" options a lot simpler.

Essentially I have added Sort button, see below.
It takes the list of items and resorts in Alphabetical order.

**Before Change**

[![Before Change](https://i.stack.imgur.com/DI1o6.jpg)](https://i.stack.imgur.com/DI1o6.jpg)
**After Selecting Button**

[![After Selecting Button](https://i.stack.imgur.com/sVadn.jpg)](https://i.stack.imgur.com/sVadn.jpg)

After the list is resorted, just hit the save button.

If your interested in code, just message me to work something out.

Regards