Each DTD in the repository has a unique Public Id.
Astoria maintains a Public Id Map that you can view using the Workbench Ribbon. Select the Administration tab, then click Public ID Map. The Details view displays a list of DTDs in the repository.
Select a DTD from the list, then issue the Locate command to find where the DTD is stored in the repository.
DTDs in the repository can specify more than one Public Id. A Public Id may reference a specific version number (for example, -//OASIS//DTD DITA 1.3 Concept//EN
), or can be unversioned (for example, -//OASIS//DTD DITA Concept//EN
).