The data center router, 1.1.2.2 has a default route of 1.1.2.1, the Internet. So when it receives a packet over the VPN destined for the Internet it simply routes, NATs in the case of IPv4, it out to the Internet.
That said you’d also have to adjust the /ip ipsec policy on the home router for the destination address to match any possible or at least the IPs for the HTTP / HTTPS sites you want to visit.