Despite the TXT format, txt to caf conversion is not related to any kind of text export, it's actually audio conversion between a specific sound sample from from Steinberg LM-4 (uses .txt extension for some reason) and Apple Core Audio Format.
We have not found any particular use for this conversion, perhaps it is export for apps available on macOS only (often supports CAF). But some audio sample converters list this conversion as possible and these are most likely your best option how to convert txt to caf.
Updated: September 19, 2023