President Donald Trump and North Korea’s Kim Jong-un are holding their highly anticipated summit—the first-ever meeting between the heads of the two countries—on Tuesday morning in Singapore. The event has been meticulously planned: where both countries are staying, who sits where in the room, what they’ll drink when they toast. But the most interesting detail to emerge might be that Kim reportedly brought his own toilet to the summit. Why would he do that?

Because he always does it to protect his excrement. It’s normal for these kinds of meetings to be rigidly choreographed. And the stakes—and tension—are higher than normal as the U.S. prepares to take on the task of persuading North Korea to abandon its nuclear arsenal and Kim maneuvers to take position as a legitimate world leader. The two leaders are to meet in Singapore, neutral territory, and even then, they will have their own luxury hotels as bases, protected by their own heavily reinforced security details.

The summit is especially eventful for Kim. It was the first time a North Korean leader has flown abroad in 32 years and Kim’s first international flight since he took over for his father in 2011. South Korean media have reported that Kim flew to Singapore with two decoy planes and that he brought his own food and bulletproof limousine for the summit. (One of his planes, the Independent reported, is Chinese, likely lent out with U.S. approval as an exception to the United Nations resolution banning member nations from loaning aircraft North Korea.)

The toilet is reportedly a regular precaution for the leader, so it only makes sense he’d bring it to this monumental event. Kim has had personal toilets installed in his various modes of personal transportation and brings one with him when he visits sites around his own country. The reason, according to Lee Yun-keol, a guard who defected from the country in 2005, is that “the leader’s excretions contain information about his health status so they can’t be left behind.” South Korean media have similarly reported a portable toilet “will deny determined sewer divers insights into to the supreme leader’s stools.”

Assuming that rationale is true, and that there were people willing to dig for this kind of evidence, there is a small amount of validity to those concerns. Kim, it seems, is more aware than the average person of the telltale signs feces can reveal: He reportedly already has his own doctors examine his stool periodically to monitor his health. From human excrement, they could learn about someone’s diet and about recent constipation. If they got into the gut bacteria, they might learn what we already know—about Kim’s obesity and smoking habits, for instance—and possibly find hints at problems such as hypertension or diabetes. If there was blood in his stool, there could be signs of internal bleeding, cancer, or other dire health problems.

Even if Kim is in perfect health, he might still want to keep any news of his health under wraps. A lack of news about his personal health, as well as any other personal information, could make for a useful negotiating factor: Kim knows more about the publicity-loving U.S. president than Trump knows about him. Or Kim could also just be an odd man.

That said, it seems doubtful someone would wade through sewage for some dietary intel. The precedent that has been cited in discussions of Kim’s toilet is that of, possibly, Joseph Stalin. According to Russian newspaper reports dug up in 2016, Stalin’s secret police would secure the excrement of other world leaders and study them in a secret lab to construct psychological profiles. Most notably, a former Soviet agent reported that Stalin’s spies collected waste from Mao Zedong from special toilets they installed for a 1949 visit to Moscow. The study of human feces to learn about the microbiome is an increasingly popular area of research, as scientists debate how much we are really shaped by the bacteria in our guts. But it’s still a stretch to say you can learn anything about how someone thinks from his poop.

Explainer thanks Isaac Stone Fish, international affairs journalist and senior fellow at the Asia Society.