System types can be extended but not renamed or deleted. They are displayd in overview lists.

If a form is extendable it will be possible to add custom types. System types are single select only (E55 linked with P2).

Form Domain Extendable System Types
Actor Actor Relation OA7 Actor Actor Relation (directed)
Bibliography E31 yes Bibliography
Edition E31 yes Edition
Event E6,E7,E8,E12 yes Event
Group E74 yes
Information Carrier E84 yes Information Carrier
Involvement P11 Involvement
Legal Body E40 yes
Member P107 Actor Function
Person E21 yes
Place E18, E53 yes Place
Administrative Unit*
Historical Place*
Source E33 yes Source
* Administrative Unit and Historical Place are not types but locations (E53) which can be linkded with P89 to the location (E53) of a physical thing (E18). Multiple selection is possible.