It appears to be some custom debugging code implemented in OpenXPKI::Debug. The POD at the bottom of the file describes it a bit.

In reply to Re: Strange and special comments in OpenXPKI Code in the form ##! 2: "new: class instantiated" in OpenXPKI Code by haukex
in thread Strange and special comments in OpenXPKI Code in the form ##! 2: "new: class instantiated" in OpenXPKI Code by ait

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