How in a file is a class called by its unqualified name?

Question

Yii

Faced the following example: There is a file, a namespace is set in it and several more spaces are connected. further in this file there is a link to the Blog class (an instance of it is created, its namespace is imported) . now the question is: the link uses an unqualified name (because the name is without a prefix) and according to the article ( https://habrahabr.ru/post/72097/) the program should not find this class, since it will look for matches only in its namespace (in this case in namespace backend\controllers; ). nevertheless everything works...

Answer 1

or by connecting the fully qualified class name we are connecting the class itself?

Answer 2

declared via use, used it is
not declared - searched in backend\controllers