Analysis of datetimezone settings in timezone phpini

Although I know that this parameter means "People's Republic of China", there is no such parameter in the official documents. There are only parameters such as Asia/Shanghai, Asia/Hong_Kong, etc. Why can it be set to RPC here? Can anyone give me some advice? Where exactly are the parameters? It seems that there is indeed no such parameter in the official documents, I am confused. Generally, it is set to Asia/Shanghai
I have been using xampp for a short time. Today, in order to correct the php acquisition function, it is to obtain the server time.
Since php5.1.0, the date.timezone option has been added to php.ini, which is turned off by default. The displayed time is all Greenwich Mean Time, which is exactly 8 hours different from Beijing time.
Method found online:
Modify the php.ini file, search for ;date.timezone = , remove the semicolon in front and add the time zone after "=".
For example: Asia/Chongqing (Chongqing), Asia/Shanghai (Shanghai), Asia/Urumqi (Urumqi), Asia/Macao (Macau), Asia/Hong_Kong (Hong Kong), Asia/Taipei (Taipei), PRC
Example
; date.timezone =
Change to:
date.timezone = Asia/Shanghai
The method is very simple. But under xampp, changing the php/php.ini file has no effect. Later, I searched online and found out that damn xampp, put php.ini under apache/bin and modify the php.ini in it to be useful.

The above introduces the analysis of datetimezone settings in timezone phpini, including timezone content. I hope it will be helpful to friends who are interested in PHP tutorials.