switch: What customizability for animations should be supported?

I am interested in nailing down what the use cases for <switch> are.
It seems like rendering content on top of the two sides of the track and the thumb are important.

In @gfellerph's new switch explainer I saw this:

Findings (from 44 analyzed Design Systems):

• 70% of Design Systems don’t display any content inside their switches
• 30% display content on the track
• 18% display content on the thumb
• 88% use the background color transition animation
• 16% use a track slide animation

For the "background color transition animation" and "track slide animation", does the design system allow the developer to customize the animation itself? Or does it just mean that the design system has an animation that is not customizable?

I am sure that <switch> will have an animation by default for these things, but do we need to provide developer controls to change how they work?

Start with @gfellerph's switch explainer and its analysis of 44 design systems. Clarify whether background-color transitions and track-slide animations need developer controls, alongside content on the track and thumb. Done means the switch requirements and supported customization options are agreed and documented.