Lets say we have a plugin that does stuff and queues up an adhoc task, and it has custom data of {course: 12345}

In it's own logs it knows that the custom data was, it would be very nice to be able to deep link into the task logs page filtered to just the specific tasks we are interested in:

/admin/tasklogs.php?customdata=course:123

This would show all the instances of this task type with that specific custom data.

Or you should be able to search by the adhoc task id and see all the instance of that run (maybe is failed twice and then ran) like this:

/admin/tasklogs.php?taskid=2641

This is blocked by report builder generally not having deep links (see MDL-73292), and specifically here by not being able to filter via either the adhoc task id, or the custom data.