Currently, authors templates are stored as `digikam\template.xml` file in user profile which is tied to user per se (and on Windows, on a throwable place which is also tied to computer, see #382358).

It means thant on a multi user scenario, one user can add new people labels and everyone can use and apply them, but if one user adds one author template, no other user can set it on a photo.

The author template contains metadata to be set on pictures, and is kind of metadata itself. The same way you can set a people name on a face by browsing the tag list, you can set an author from the author drop-down list, but this author list is not stored in database so unlike people tag list, author list is not shared among users.