Extract indexed URLs from Google CSE? | NewProxyLists

Hey guys, I need to know if it 's possible for other users to get the URLs used by a Google custom search engine.
I have a list of links with 500 websites and I want to put them in a CST.

I'm afraid other visitors may extract them and perhaps clone the CSE.
I know everything is technically erasable, but other than that, are there any other methods known to the public to get index pages of a CSE? (Github scripts, software, PHP tips)?

Is there perhaps a better way to create a custom search engine today without Google?