In mainland China, anonymous reporting exists in name only.
In some departments, anonymous reports are still nominally accepted, but all anonymous reports are rejected due to the inability to verify the veracity of the report.
There was a case in the past.
People report local authorities anonymously to the central authority by sending letters by post.
When the letters are forwarded from the central authority to the department being reported, staff investigate who sent the letters by tracking CCTV.
I therefore recommend that all whistleblowers who report truthful content fill in their true personal details.
This way your report may be accepted more quickly.
For people with personal vendettas, or inaccurate content.
Anonymous reporting is not a lawless place.