The article tries to define it:
> an accident in a laboratory or during a research field trip
Which, yes, is incredibly vague. I give them credit for at least ruling out the "Evil Chinese Scientists intentionally create and release deadly virus!" bullsh*t.
One plausible "lab" scenario: A baggage-hauling laborer caught the proto-COVID-19 virus in a bat-filled cave during a routine "collect samples of germs from bats" expedition, then unknowingly spread it back in Wuhan.
My opinion: For useful-fact-oriented folks, the Lab Hypothesis is mostly a tedious waste of time. For those motivated by hot-button emotions, attention-seeking, etc., the most lurid and cartoonish versions of the Lab Hypothesis are by far the best. If they can conjure such images in the minds of their audience - withOUT having to spell them out, for reality-checkers to attack - then all the better. Hence the remarkable scarcity of Lab Hypothesis explanations.