China just quietly wrote off a chunk of Cameroon’s debt. Why the secrecy?

“Last week, Chinese Foreign Ministry spokesperson Hua Chunying told CNN: “China agreed to waive the interest-free inter-governmental debt that Cameroon had not paid back by the end of 2018.”
That debt was worth $78.4 million. Cameroon’s total debt is 5.8 trillion Central African CFA francs ($10 billion), about a third of which is owed to China, according to the International Monetary Fund.
In short, this was a tiny slice of Cameroon’s liability to China.
So why the initial secrecy?”