How do ISPs send their own pages when a user is trying to access a blocked site?

I know that some ISPs send block pages(like “This site has been blocked because … “) over HTTP by sending a fake 301/302 redirect.

I also know that instead of sending a block page, some ISPs simple send RST to terminate the connection or do nasty things with DNS when blocking an HTTPS site.

But can they send a block page over HTTPS? And if possible, I’d like to know some other methods of blocking sites(both HTTP and HTTPS).