What is the special use of php http custom headers?

recently in the interview, I was asked: can the http header be customized?
since I usually don"t care much about and use custom http headers, I read this article directly after saying that I don"t know
: https://blog.csdn.net/fdipzon.
also tried. There is no problem with the code, but I just don"t understand two questions: what is the use of
1.http custom headers?
2. What are the scenarios for custom use?

Php
Mar.09,2021

http Custom header is mainly for security reasons. You can put some token authentication information in the header request header to simulate real users.
usage scenario:
1, authorization authentication of api
2, crawler forged header information
3, cross-domain setting


the custom header here should be the response header information
can be used to set the page cache HTTP status code page jump tell the browser how to parse the page and so on

MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b3f349-2c47b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b3f349-2c47b.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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