Why did he say "it was about" not "it is about" while he's talking right now?
Native speaker’s answer
Rebecca
Harry is referring to an incident that occurred in the past, which is maybe why he has used the past tense "was" instead of "is" in this context. We'd have to hear the earlier part of the conversation between them to be sure, however. Generally, "was" and "is" can both be used in situations like this one. Ex: A: How can I help you today? B: It's about the cake I ordered last week. It was smushed when it arrived. Ex: A: What was the book about? B: It was about the adventures of a golden retriever named Pudding.