The notation /site type or /site type/site name is used to specify the type and the URL-encoded name of the site where that resource resides. It can be:
Omitted if the resource does not relate to a site but is specific to your environment. This applies, for example, to operators, roles, computers, and so on.
Set to master if you logged in as a non-master operator and the category is defined on the master actionsite.
Set to /operator/operator_name if the category is defined in the operator site of a specific non-master operator (NMO).
Set to /external/site name if the category is defined on an external site. For example, /api/tasks/external/BES Support identifies the category of tasks available on the BES Support site.
Set to /custom/site name if the category is defined on a custom site of your BigFix environment.