This improvement corresponds to the Moodle administrator's tool: Bulk user actions. It resolves the problem of fixed list of actions in this tool and makes adding new ones easier.

The updated tool has plugin structure: all actions are stored in /admin/user/actions/ folder; each action has its own folder with index.php, other scripts if necessary, and lang folder to store strings.

The "standard" actions were reorganized to comply to this structure, and two more actions were added: bulk user enrolment and bulk user unenrolment. Those two simplify the procedure of enroling/unenroling multiple users to/from the same list of courses with the same roles.

Also, a small update of user filters class is added here - a button to replace all active filters with new one.

The tool is divided on subtasks, and each of them is installed via applying the corresponding patch. Subtasks also contain details about implemetation.

Bulk user action plug-in structure looks very similar to gradebook reports; we've tried to make it systematic and ready to be implemented in the standard Moodle distrib. In fact, only change which is necessary to do it is "registering" bulk user actions in the core function of retrieving language string locations. This would remove necessity in one string argument in each get_string call within actions. Currently "additional locations" are used, so the installing of update is easier.