The mysqlnd plugin API is simply part of the MySQL
   Native Driver PHP extension, ext/mysqlnd.
   Development started on the mysqlnd plugin API in
   December 2009. It is developed as part of the PHP source repository,
   and as such is available to the public either via Git, or through
   source snapshot downloads.
  
   Plugin developers can determine the mysqlnd
   version through accessing MYSQLND_VERSION, which
   is a string of the format mysqlnd 5.0.7-dev - 091210 -
   $Revision: 300535
, or through
   MYSQLND_VERSION_ID, which is an integer such as
   50007. Developers can calculate the version number as follows:
  
| Version (part) | Example | 
|---|---|
| Major*10000 | 5*10000 = 50000 | 
| Minor*100 | 0*100 = 0 | 
| Patch | 7 = 7 | 
| MYSQLND_VERSION_ID | 50007 | 
   During development, developers should refer to the
   mysqlnd version number for compatibility and
   version tests, as several iterations of mysqlnd
   could occur during the lifetime of a PHP development branch with a
   single PHP version number.