I've been trying to use the Atto plugin template (https://github.com/justinhunt/moodle-atto_newtemplate) to try and create my own Atto plugin. I've made the changes outlined in the README, and ran shifter to create the build folder with 3 js files in it.
As far as I can tell, my structure matches every other plugin in lib/editor/atto/plugins.
I'm able to see the plugin in configuration, and it's showing up in the Atto Toolbar Settings, but, when I pop open a text editor, I don't get an icon, and the console logs moodle-editor_atto-editor: Plugin 'testplugin' could not be found - skipping initialisation
Has anyone come across this before? What am I missing?