Adapting to Checkout Extensibility: Is it possible to add scripts to it?

[mako-reactive]

Hello Shopify Community,

As we will be required to transition to Checkout Extensibility by August 13, I have a couple of concerns:

• Scripting: With the elimination of "checkout.liquid", what happens to existing scripts that modify checkout elements? Is script integration now completely obsolete in the new system?
• Phone Number Validation: Is there a workaround or method within Checkout Extensibility to ensure the phone number field only accepts numbers, with no spaces, since it seems we can't add scripts anymore?

Thanks for your guidance!