Specifies default permission to use in case folder is supposed to be created below a certain parent folder.
The value is a pipe ('|') separated listing of expressions; each expression defines the default permissions
for a denoted parent folder. Currently the reserved folder identifiers 2 and 15 are considered as 2
denoted the public PIM folder whereas 15 denotes the public Drive folder.

An expression starts with the parent folder identifier followed by '=' character; e.g. 2=.
Then there is a comma-separated list of permissions to assume per entity (user or group).

Each permission either starts with user_, admin_user_, group_ or admin_group_ (the prefix admin_ controls
whether the entity is supposed to be set as folder administrator) followed by the numeric entity identifier.

Then an '@' character is supposed to occur and finally followed by rights expression. The rights may be dot-separated
listing (<folder-permission> + . + <read-permission> + . + <write-permission> + . + <delete-permission>) or one
of the tokens viewer, writer or author.

More formally
expressions = expression (