PHP $ _ SERVER details

Some server information is often used in php programming. I paste the commonly used information in highlighted mode, and the rest will be placed behind it for future reference. The code is as follows:
$ _ SERVER ['http _ ACCEPT_LANGUAGE '] // browser language
$ _ SERVER ['remote _ ADDR '] // IP address of the current user.
$ _ SERVER ['remote _ host'] // HOST name of the current user
$ _ SERVER ['request _ URI '] // URL

$ _ SERVER ['remote _ port'] // PORT.
$ _ SERVER ['server _ name'] // NAME of the SERVER host.
$ _ SERVER ['php _ SELF '] // file name of the script being executed
$ _ SERVER ['argv'] // parameters passed to the script.
$ _ SERVER ['argc '] // Number of command line parameters passed to the program.
$ _ SERVER ['gateway _ interface'] // CGI standard version.
$ _ SERVER ['server _ soft'] // string of the SERVER ID
$ _ SERVER ['server _ protocol'] // name and version of the communication PROTOCOL on the request page
$ _ SERVER ['request _ method'] // request method for accessing the page
$ _ SERVER ['query _ string'] // query string.
$ _ SERVER ['document _ root'] // ROOT directory of the DOCUMENT where the script is currently running
$ _ SERVER ['http _ ACCEPT '] // Accept of the current request: content in the header.
$ _ SERVER ['http _ ACCEPT_CHARSET '] // The Accept-Charset of the current request: content in the header.
$ _ SERVER ['http _ ACCEPT_ENCODING '] // The Accept-Encoding of the current request: content in the header
$ _ SERVER ['http _ connection'] // CONNECTION of the current request: content in the header. For example, "Keep-Alive ".
$ _ SERVER ['http _ host'] // HOST of the current request: content in the header.
$ _ SERVER ['http _ referer'] // URL of the previous page linked to the current page.
$ _ SERVER ['http _ USER_AGENT '] // User_Agent of the current request: content in the header.
$ _ SERVER ['https'] // if accessed through HTTPS, it is set to a non-null value (on); otherwise, off is returned.
$ _ SERVER ['script _ filename'] # The absolute path name of the currently executed SCRIPT.
$ _ SERVER ['server _ admin'] # Administrator information
$ _ SERVER ['server _ port'] # PORT used by the SERVER
$ _ SERVER ['server _ SIGNATURE '] # a string containing the SERVER version and virtual host name.
$ _ SERVER ['path _ TRANSLATED '] # Basic PATH of the file system where the current script is located (not the root directory of the document.
$ _ SERVER ['script _ name'] # contains the path of the current SCRIPT. This is useful when the page needs to point to itself.
$ _ SERVER ['php _ AUTH_USER '] # When PHP runs in the Apache module mode and uses the HTTP authentication function, this variable is the user name entered by the user.
$ _ SERVER ['php _ AUTH_PW '] # When PHP runs in the Apache module mode and is using the HTTP authentication function, this variable is the password entered by the user.
$ _ SERVER ['auth _ type'] # When PHP runs in the Apache module mode and is using the HTTP authentication function, this variable is the authentication TYPE