What’s unusual about this passage from Great Expectations?

It is not much to the purpose whether a gate in that garden wall which I had scrambled up to peep over on the last occasion was, on that last occasion, open or shut. Enough that I saw no gate then, and that I saw one now. As it stood open, and as I knew that Estella had let the visitors out,– for she had returned with the keys in her hand,– I strolled into the garden, and strolled all over it.

It contains a string of 15 letters that reads the same forward and backward:

It is not much to the purpose whether a gate in that garden wall which I had scrambled up to peep over on the last occasion was, on that last occasion, open or shut. Enough that I saw no gate then, and that I saw one now. As it stood open, and as I knew that Estella had let the visitors out,– for she had returned with the keys in her hand,– I strolled into the garden, and strolled all over it.

Reader Eric Harshbarger has been searching for such strings in literary texts. Here are his finds, and here’s a nifty tool he made that will find the longest palindromic substring in a given passage.

(Thanks, Eric.)

12/11/2021 UPDATE: Eric wonders what’s the longest sensible text one might construct that doesn’t contain any such substrings (an example: “We view uncopyrightable material on Wednesdays”). Add your ideas here.