As of 2020.1, PHPStorm provides stubs for \BlackfireProbe internal class, which is provided by the Blackfire extension. These stubs give you code completion on all available methods of BlackfireProbe class.

Blackfire stubs are not enabled by default in PHPStorm. To activate them, you need to:

  1. Go to PHPStorm settings;
  2. Go to Language and Frameworks, then PHP;
  3. Click on PHP Runtime tab;
  4. Unfold Others, and check blackfire in the list;
  5. Validate your change by clicking OK.