The cat in Old Cat is said by the author to be the most common civet cat. Why?

The cat in Ji Xianlin's essay "The Old Cat" is described by the author as the most common civet cat, because the original text says that this cat has no characteristics, but is just the most common civet cat.

The original text is as follows:

It has no features, just an ordinary civet, with tiger stripes, black or yellow, not beautiful. However, there are some differences from ordinary cats. It has two bright eyes. When both eyes are open, it is really a tiger-tiger, so it is named tiger.