The way log entries are generated is via the event API. Code will create an event with the data to log, then 'trigger' it to cause the log entry to be created. Docs are here, but the are a bit verbose. https://docs.moodle.org/dev/Event_2. The helpful thing to know is that the even classes will always be in places like .../classes/event/event_name.php throughout the Moodle code. So, for example mod/quiz/classes/event/attempt_deleted.php. Then you can search the code for places where that event class is referred to, like https://github.com/moodle/moodle/blob/0e1e1e5586a1f43c951d9a399243220a3ccf882c/mod/quiz/locallib.php#L436.
Hopefully it is clear how what is defined in that class relates to what is written to mdl_logstore_standard_log.
(LOL at the proposed course title.)