What are "Watermarked" ballots?

"Supposedly, President Donald Trump and the Department of Homeland Security set up Democrats (who allegedly aimed to cheat) by secretly watermarking "official ballots.""
https://www.politifact.com/factchecks/2020/nov/06/facebook-posts/did-president-trump-issue-secret-watermarks-ballot/

"There has been a rumor floating around the internet the last several days about secretly watermarked voting ballots. The reason for these ballots was that the election fraud we are seeing was anticipated by the Trump Administration and they put countermeasures in place. We are told that the ballots were secretly marked with watermarks specifically designed to detect voter fraud."
https://visionlaunch.com/breaking-bombshell-did-democrats-fall-into-a-trap-set-by-trump-watermarked-ballots/

"According to former intelligence officer Steve Pieczenik, President Trump assumed Democrat tomfoolery would be needed to prevent him from securing a second term via the 2020 election.

In order to ensure the election remained fair, POTUS devised an advanced trap.

Hidden, trackable watermarks were allegedly put onto ballots so they could be verified if necessary."
http://memoryholeblog.org/2020/11/06/steve-pieczenik-reveals-2020-ballots-watermarked-with-qfs-encryption-video/

"Posts shared on social media claim that the U.S. Department of Homeland Security (DHS) has marked all authentic election ballots with “non-radioactive isotope watermarks” in order to be able to identify fraudulent replica ballots. Posted amid extended vote counts in key battleground states, this claim is false. States themselves, rather than federal agencies, are responsible for designing, producing, and auditing their ballots, not the DHS"
https://www.reuters.com/article/uk-factcheck-watermarks-idUSKBN27N0GN

"“This is really a sting operation, contrary to what everyone else said. We watermarked every ballot with QFS blockchain encryption code. In other words, we know pretty well where every ballot is, where it went and who has it, so this is not a stolen election,” said Pieczenik."
https://defconnews.com/2020/11/06/did-trump-set-vote-fraud-trap-for-dems-with-watermarked-ballots/

“What happened was we marked—watermarked—every ballot with what's called the QFS block chain encryption code.”
https://nexusnewsfeed.com/article/geopolitics/ballot-fraud-sting-operation-playing-out-in-the-usa/

"Other claims assert that small dots on the paper ballots are covert watermarks."
https://www.thatsnonsense.com/has-dhs-and-trump-set-up-secretly-watermarked-ballots-to-detect-fraud-fact-check/

"Dems print extras, not knowing about non-radioactive isotope watermarks on “official ballots”.

Military sting operation."
https://www.truthorfiction.com/special-paper-watermarked-ballots-conspiracy-theory-spreads-on-social-media/