This statement is no longer maintained. An updated version was published on 29 June 2020. [hyperlink in the original]
That’s a fancy way of saying the WHO has made significant corrections.
For months, this organization misled us all. It implied that authorities within China had sounded the coronavirus alarm. The original WHO timeline said the Wuhan Municipal Health Commission had reported a cluster of cases of pneumonia. Here’s a screenshot:

old timeline; source here
The turquoise-coloured text is a hyperlink to the WHO’s first COVID press release, which likewise began with this misleading statement:
On 31 December 2019, the WHO China Country Office was informed of cases of pneumonia of unknown etiology (unknown cause) detected in Wuhan City, Hubei Province of China. [bold added]
Every nation is legally obligated to promptly inform the WHO when medical cases of this kind arise. The procedure is straightforward. Designated individuals in national governments (not municipal health commissions) must contact designated WHO officials. In this case, information was supposed to flow from the top tier of the Chinese government to an individual in the WHO’s Western Pacific Regional Office, based in Manila.
But that didn’t happen. The new, much longer text, admits the alarm was actually raised by members of the WHO’s own office in China, located in the diplomatic district of Beijing, just down the street from the Canadian and German embassies. That office wasn’t informed, as the press release puts it. Instead, it noticed, entirely of its own accord, a media statement posted on the Internet by Wuhan health authorities hundreds of miles away.
That same day, a different arm of the WHO noticed a news report on an online platform that monitors infectious diseases. It said an “urgent notice” had been issued by Wuhan health officials, due to hospitals having already treated a series of patients with “pneumonia of unknown cause.”