Calendar plugin for wordpress site

Status as of 2026-03-31 when codex credit ran out:

Removal of plugin did not work. Need to set all files owner to www-data. - done
Deletion of event in ui doesn't delete event in thunderbird - done
Cannot subscribe to an empty calendar in thunderbird - ok
Click inside month cell doesn't add event. - cannot reproduce
Login pane hidden under website hero/banner image - done
Updating an events description via caldav creates weird sequences, e.g. a space ends up as: text/html,%C2%A0":
In a private window, Click on event from not-logged-in calendar page shows event as a dialog box, it should show it as a panel with a subset of the edit event panel - i.e. the title, category, location, start and end and description. -