Likely a reference to the specific site or network where the media originated.
As we look back at the digital landscape of October 2015, we see a "Wild West" of naming conventions. Today, AI-driven tagging does this work for us. But the era of Crystal Clark and manual metadata represents a time when the internet was still being organized, one "fixed" file at a time.
It serves as a reminder that behind every video or image we consume, there was a human being—in this case, someone making sure the file stayed "fixed" for the long haul. Legacy of the 2015 Web