org-special-properties

org-special-properties is a variable defined in `org.el'.
Its value is

("TODO" "TAGS" "ALLTAGS" "DEADLINE" "SCHEDULED" "CLOCK" "CLOSED" "PRIORITY" "TIMESTAMP" "TIMESTAMP_IA" "BLOCKED" "FILE" "CLOCKSUM" "CLOCKSUM_T")

• This variable may be risky if used as a file-local variable.

Documentation:
The special properties valid in Org-mode.

These are properties that are not defined in the property drawer,
but in some other way.