The Maintenance database stores everything related to the Maintenance and Calendar modules, including task configurations, the task log, change history, calendar events, and the registry of known remote systems.
Custom calendar events — title, object, color, creator, description, and start/end timestamps in milliseconds. Imported events are tagged with the subscription they came from.
calendar_config
Key-value configuration for the calendar, such as the reminder offset.
ics_subscriptions
Calendars imported into the project. One row per import, holding its name, the file path it came from, its type, visibility in the calendar, and any colour override. A database carried over from a build with the REST plugin can also hold rows of the retired url and nager types. See Calendar — Extending.