This pen is called Breadcrumbs and was introduced in IntelliJ IDEA 2016.2
Breadcrumbs . Until now, crackers were only available in HTML and XML. Now, breadcrumbs also work in Java, where instead of tags, they let you navigate through classes, lambda expressions, and methods.
This is a pretty useful pen, but if you donβt like it, you can turn it off by going to Settings / Editor / General / Appearance / Show breadcrumbs. 
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