Howard Miller

Answering my own question, the namespace seems to be 'subpluginname_mysubplugin' - that is, the name of the subplugin given in subplugins.json - underscore - name of the subplugin. Although, again dissapointingly, I couldn't find this documented anywhere so I still could be wrong.

Followup question.... how do class names work.

That is... if I have a class/file - local/myplugin/subpluginsdir/mysubplugin/classes, what would the namespace and a the name of a class therein look like?

It does, thanks. I had mostly fumbled my way to something that works but I wasn't completely confident it was correct

I usually try to work out what the "edit" URL would be for the block. I'm not familiar with that block so can't be much more helpful.

Do you mean, https://moodle.org/plugins/enrol_autoenrol

Could be worth posting in https://github.com/bobopinna/moodle-enrol_autoenrol/issues, as it's entirely likely that nobody in these forums is familiar with this plugin.