These are naming restrictions for DCM databases.
These characters cannot be used in the database identifier of the DCM database.
In addition to the restricted characters listed, the database identifier cannot be longer than 8 characters and cannot be the name "probtrac". The database identifier cannot contain the version delimiter by default. This can be changed by the allow_delimiter_in_name attribute.
The DCM database identifier is case-sensitive. In any DCM cluster that uses lowercase databases, DCM database identifiers must be unique without respect to case. That is, you must not use database identifiers that are only different with regards to case.
You cannot use characters a-z, A-Z, or 0-9 for the DCM delimiter. You can use "!", "~", or "=" as an alternative delimiter. The default DCM delimiter is #, the pound sign.