How and where is a 404 error generated in Bitrix?

Question

1C-Bitrix

domen/blablabla
After a domain with a slash non-existent - it doesn't give a 404 error, but should
domen/salons/blablabla
Domain - slash-section existing-slash-non-existent abrocodebra without a slash at the end throws on the main one, but it should 404
with a slash at the end - normal
Tell me pliz where to dig?

Answer 1

When processing a request by the server, if it is not a file and not a directory, it goes to urlrewrite.php
Then see the rules like this. in 90% of cases there are regular curves