The discovery of triggered an extensive police response, with fears of the potential for a mass casualty event targeting the Jewish community.
Police are treating the incident as a credible terror threat and have assigned more than 100 counter-terrorism detectives to investigate those behind the plot, which was discovered nearly two weeks ago.
Where was the caravan found?
On a semi-rural road in Dural — a suburb about 30 minutes north-west of Sydney's CBD — where it was found abandoned by a resident.
It was reported to authorities on 20 January, sparking a massive multi-agency probe with more than 100 counter-terrorism investigators.
What was found inside the caravan?
Powergel explosives — commonly used in the mining industry — that could have created a 40-metre-wide blast, and a note containing the addresses of Jewish people and institutions.
The note included the words, "f--- the Jews".
NSW Police commissioner Karen Webb said on Thursday that although explosives had been found, there was no detonator with the caravan.
Police have said there is no ongoing threat to the community.
Who is investigating the incident?
More than 100 counter-terrorism detectives have been assigned to investigate. They are from NSW Police, the Australian Federal Police, the Australian Security Intelligence Organisation, and the NSW Crime Commission.
Authorities are investigating whether the caravan was abandoned strategically to be discovered by police or whether someone was going to disclose the existence of the explosives.
NSW Police also said it was also working with Victoria Police and Queensland's police.
Who has been arrested?
Arrests have been made "around the periphery", with some connected to other alleged antisemitic attacks, but those responsible remain at large, police have said.
Police have also said the owner of the caravan is in custody for "unrelated matters".
Why was there a delay in making the Dural discovery public?
The public was made aware of the incident on Wednesday — 10 days after the caravan was found.
NSW Premier Chris Minns has defended keeping the discovery a secret.
"I don't want the public to believe that over the last 10 days police were twiddling their thumbs," Minns said on Thursday.
"If the public believe that police or the government will issue a media release when they begin a counter-terrorism investigation, that is not going to happen."
He said sometimes police officers needed to "conduct their inquiries away from the media spotlight".
Federal Liberal MP Julian Leeser — whose electorate includes Dural — told ABC News he believed police should tell the community about these investigations "at the earliest possible occasion".
"That's a matter for the police and ultimately a responsibility of the premier," Leeser said.
He echoed Opposition leader Peter Dutton's comments, calling on Prime Minister Anthony Albanese and other senior Labor ministers to reveal when they found out about the incident.
Minns earlier told Sky News it was easy for some politicians to demand the information be released immediately, especially with the federal election looming.
"I would just urge everybody to let NSW Police conduct these investigations," he said.
"The stakes couldn't be higher. Politics can wait for another day."
Has the incident been labelled terrorism?
NSW deputy police commissioner David Hudson told ABC Radio on Thursday the incident hadn't been declared a formal terrorist investigation.
But he said the nature of the note listing "Jewish entities" meant NSW police had put it "in the terrorism space".
But Albanese and Minns both described the incident as being an act of terrorism.
"It's clearly designed to harm people, but it's also designed to create fear in the community, and that is the very definition (of terrorism)," Albanese told ABC Radio.
With the Australian Associated Press.
