Further searches found the same flag claiming two meanings - “Blue Lives Matter” and “The Thin Blue Line”:
https://www.amazon.com/Thin-Blue-Line-American-Flag/dp/B0120XPQ3A
“The Meaning of the Thin Blue Line Flag: The Blue represents the officer and the courage they find deep inside when faced with unbelievable odds. The Black background was designed as a constant reminder of our fallen brother and sister officers. ... Honor our Men and Women of Law Enforcement with this Thin Blue Line Flag.”
I don’t know which side was first and which hijacked the other’s idea. I apologize for initially posting without checking in more detail.
Thanks. Very complex indeed.