Hello world!
Some pdf files has a built-in index that can be used for navigation, which in most cases, are shown in the left side plate of the PDF browser, for example `evince`. If still not clear, you may think of latex generated pdf files (most of them has this structured index navigation).
How to export the index structure used for nevigation as plain text? Implementing this index navigation feature into pdf browsers like `evince` clearly needs this as in important API.
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He who is worthy to receive his days and nights is worthy to receive all else from you (and me).
The Prophet, Gibran Kahlil Gibran