We are trying to encourage plugin writers to use the config_plugins table more. Here is one thing standing in the way:

To add an admin setting that stores its value in the config table, you need to do

$temp->add(new admin_setting_configtext('allowemailaddresses', ...

for a setting that should go in config_plugins, you need.

$maxgradesetting = new admin_setting_configtext('maximumgrade', ...
$maxgradesetting->plugin = 'quiz';
$quizsettings->add($maxgradesetting);

It's not the end of the world, but it is a pain. So, what to do about it. I see 2 options:

1. Add an optional parameter to the admin_setting constructor to take a $plugin name that defaults to null. This would be awkward, becuase it woudl have to become the 5th parameter, which is a long way from the variable name, which is the first parameter. Also, adding a setting to the constructor involves changing the constructor of every single admin setting subclass.

2. Change the interpretation of the first paramter, so that you can do

$temp->add(new admin_setting_configtext('quiz/maximumgrade', ...

then in the admin setting base class, if the setting name contains a '/', parse it into the plugin name and the setting name.

I don't insist on '/'. '.' or ':' might be better. The only one we can't use is '_' becuase some admin settings already have an underscore in them.

As you can probably tell, I favour 2. because it is easier to implement.