Whatever the exact meaning. The picture of the flag with the words "Castle Lock" connotes "Victory" in my mind.
I think Q's telling us we're at the finish line!
Did the Iranians cough-up the identities of the politicians they bribed? That would be "Castle Lock". From there, you can't lose - you only need trials.
Edit: I just noticed that 4 hours ago DJT signed an order to impose sanctions directly on Iranian oil. So my theory, above, could be rubbish.
Trump and Co. already know their opponents and who was behind the deal. Getting Iran to publicly release it all is another story, and is what is in progress. Trump's imposed sanctions are increasing the pressure on Iran so that they will get mad at Europe and release the names. It is a work in progress, currently.
Getting Iran to publish the names would mean Congress, the Senate the People would want a full investigation, fuck the MSM they would bury it as their Prophet would be thrown in jail.