the original chunk is most likely stored with it in referential format such as an id in the metadata to pull from a DB or something along those lines. I do exactly what he does aswell and i have an Id metadata value that does exactly that pointing to an id in a DB which holds the text chunks and their respective metadata
Before chunking, run coreference resolution to get rid of all of your pronouns and replace them with explicit references. You need to be a bit of careful to ensure you chunk both processed and unprocessed versions in the same places but it’s very doable.
If you haven’t seen it, there’s a lovely overview of the idea in one of the SpaCy blog posts: https://explosion.ai/blog/coref
The original chunk, sure, but what if the original chunk is full of eg pronouns? This is a problem I haven't heard an elegant solution for, although I've seen it done OK.
What I mean is, how can you derive topics from a chunk that refers to them only obliquely?