doc: clarify about name in toml
@@ -155,11 +155,16 @@ example=
[internal/<plugin>/*]
status= implemented
-usedby/plugin= (ini)
-description= Internal metadata to be ignored by other plugins.
-example=internal/ini/parent could be the name for internal parent
- information of the ini plugin.
-
+usedby/plugin=
+description= Internal metadata that must be ignored by other plugins.
+ It is useful for reconstruction of information about keys between
+ kdbGet and kdbSet.
+ Always avoid to use it if there is any other metadata that
+ can be used instead.
+ For example, if a type can be represented with the CORBA
+ type system, metadata `type` should be used.
+ Only if a type cannot be represented, e.g., the `toml`
+ plugin would use `internal/toml/type`.
[line]
type= int
