IIRC, cross site loads fail. Most likely due to TLS mismatches. See: You can bypass YouTube ads by adding a dot after the domain (reddit.com) https://news.ycom

IIRC, cross site loads fail. Most likely due to TLS mismatches. See: You can bypass YouTube ads by adding a dot after the domain (reddit.com) https://news.ycombinator.com/item?id=23479435 https://news.ycombinator.com/item?id=23479435 I once submitted a bug for Mozilla, it got shot down: The site does not work as expected if you use https://youtube.com https://youtube.com. in Firefox. This can be a security issue, if you are on corporate or public-wifi DNS that is a security issue, too: if the default search happens in companyname.com. by DNS setting of that network and they offer youtube.com.companyname.com., you will get youtube.com served from evil companyname.com Why does that nowadays still exist? A good use case, if you are lazy, is that you can visit webmail.companyname.com by typing https://webmail https://webmail and being in corporate (virtual) private network, which I frequently do. Compare: URLs with trailing dots in host names (FQDN) produce cert name mismatches (for paypal) https://bugzilla.mozilla.org/show_bug.cgi?id=134402 https://bugzilla.mozilla.org/show_bug.cgi?id=134402