Identifiers are mostly used to make keywords unique, but they can also be used to specify keywords which should not be shown in the index. Identifiers are especially help full when using context sensitive help and one keyword has more links assigned to it.

E.g. consider the keyword "replace" in Qt. It is included, among others, in QString and QList. To be able to retrieve the proper documentation, there is an identifier "QString::replace" and one "QList::replace".

A global prefix, e.g. "MyApp::" is set for all keywords independent where they are located. When inheriting the prefix from the file name, the keywords get the prefix "[filename]::" where the file name is taken from the reference of the keyword. The file name is just the base name, i.e. without any directory or extension.