لماذا لا يمكنني رؤية جميع العلامات في موقع يمكنني الوصول إليه؟

In a site that I use as a member, I know that there is a tag called “quality” because some of the topics I have access to show it as a tag.

However when I go to browse all tags I do not see this tag listed.

Why could that be?

Is the tag on topics in a public category or is access to the category limited to some groups? (Do the categories of the topics have a lock icon?)