I believe this referring to a discussion on an article about the use of Stingray-type devices (If someone can provide the link that would be great), particularly how their use was concealed from courts when obtaining a search warrant. Instead of telling the court that the information was obtained by use of a Stingray, they told the court the information came from a "confidential source"

you're correct. I'll try to find the source later, but this was exactly the case. Police would install the tracker or whatever, then tell the judge it came from a confidential source (the legal definition of which is a person). Meaning that police were outright lying to judges.

edit: source -- https://news.ycombinator.com/item?id=7931548

Would you link to the source you're referring to?

It's confidential, releasing it would impact [pick one] a) an ongoing investigation b) the safety of undercover agent c) national security. But, trust us, source had good reliable info.

[edit: to the totally confused. My comment is political satire. And it purposefully misidentified which "source" you were referring to for purposes of bitching about USA law enforcement.]

Now I'm totally confused.

e.g. "a confidential source" that we saw on here yesterday.

That implies some confidential source was featured on HN yesterday. Linking to that post should do none of those things.

He's referring to the practice of Florida law enforcement claiming that the basis for a warrant came from "a confidential source" (which, in the context of warrants, appears to mean "an actual person"), when in reality they were using information captured via IMSI capturers ("stingrays") -- devices which MITM cell phone connections to surveil users of the cell network.

In short, he was saying that we can reliably expect many warrants to have been obtained by law enforcement lying to judges. Based on the information (lies) presented to the judges, they're going to approve the warrant, because they operate on the premise that law enforcement wouldn't lie to them.