#next-on-pages is a channel, you can click on it to jump to it, or navigate on the left side (if on desktop) to it. It may be hidden as well depending on the settings you picked in the <id:customize>
If it's IPs, he could use an IP List instead of putting them all in the rule. IP Lists can have 10,000 items. Otherwise, the limit above is the only one I know of: 4,096 characters for the entire expression
Depending on what you are doing, you may be able to use other operators to fit more. For example, if you wanted all subdomains, just use Starts WithStarts With and such.