This has nothing to do with DNS or browser. This is strictly web server configuration.
Browser uses "Host:" header specifying the NAME of the the website which it wants to get and the rest is up to web server to get the correct content.
It looks like this domain is in a broken state in terms of DNSSEC validation where ideally it should not resolve at all. (SERVFAIL status is the expected outcome for any validating resolver.)
If you look at for instance DNSViz output, you can see that the delegation has a DS record (specifies a DNSSEC key that is used for signing the zone) which refers to a ...
Then one website could reside at 11.222.333.444/example1 and another at
Nope. There is ONE website, residing at 11.222.333.444 - what you put into this website, including folder with "fake" other sites, is not a DNS issue.
BUt you rquestion also mixes this up - the 2 websites would be on the same address, but NOT ...
Other answers forget about one thing, far more important than speed: correctness.
If example.com has ns1.example.com as nameserver, on a query for NS the registry will send ns1.example.com in the answer section, and the glue records (A and AAAA) in the DNS packet additional section.
The resolver getting those CAN use the glue record because it sees that it ...