I've enabled community in Sandbox and used Napili community template for community Builder. We need to implement Captcha process in Self Register Page. So we need to edit Standard Self Register Lightning Component. But the Community Lightning Components are missing in my Sandbox for edit(Developer Console). But its visible in Community Builder. I've also checked in my Developer Org , in which we've all Lightning Components related to Community. How to enable it. Please advise on this.
When you create a community for the first time in an org, Salesforce generates a few different lightning components for you. One of these components is called "selfRegister".
It's not very intuitive, but if you uncomment the very first line in the selfRegister component, then you'll get a component named "Custom Registration" or something similar next time you open or refresh community builder.
You might have to add the new found custom registration component onto the Registration page, but once you start poking around a bit, you'll notice that the component changes when you update it in your IDE of choice.
I'd suggest leaving this component alone though, and creating your own Self Registration component (make sure the component uses the forceCommunity:availableForAllPageTypes interface).
To get around the CDN limitation, I downloaded both the api.js as well as the timestamped js and stuck them into static resources, and got captcha working at least for now.
Others, like mentioned in this link have had success with a combination of Visualforce along with their lightning component(s).