There are three expungements here. The first covers up a method of detecting and tracking SCP-1000, the second serves to give the impression (again, through absence) that the Foundation is losing ground against SCP-1000, the third one implies intelligence among the SCP-1000 community. These expungements directly impact the way you read the paragraph; they introduce a very measured level of confusion into the document that is designed to throw the reader off base, make the reader uncomfortable. This principle is the core of what expungement looks like when done correctly.
The most famous incident in Huineng’s story concerns a dharma contest. One day Hongren challenged his charges to each write a verse ( gatha ) distilling their understanding of their “original natures.” He promised to read them and award his robe (a symbol of dharma transmission; some versions of the story include Hongren’s begging bowl) and the title “Sixth Patriarch” to the student demonstrating true realization. The task quickly devolved onto the shoulders of the head monk, Shenxiu, who, it was assumed, would be the Master’s likely successor. Shenxiu, however, was full of doubt and spent a tortured night considering his options. Finally he stole out and wrote his verse anonymously on the wall of the new dharma hall: