Is there a description somewhere of what the log_params mean in this query?

MariaDB [enwiki_p]> select log_params from logging_logindex where log_namespace = 2 and log_title = 'RoySmith-testing' and log_type = 'block' order by log_timestamp asc;

+---------------------------------------------------------------------------------------------------------+

| log_params                                                                                              |

+---------------------------------------------------------------------------------------------------------+

| a:3:{s:11:"5::duration";s:9:"5 minutes";s:8:"6::flags";s:11:"noautoblock";s:8:"sitewide";b:1;}          |

| a:3:{s:11:"5::duration";s:9:"5 minutes";s:8:"6::flags";s:20:"nocreate,noautoblock";s:8:"sitewide";b:1;} |

| a:0:{}                                                                                                  |

+---------------------------------------------------------------------------------------------------------+

3 rows in set (0.00 sec)