sphinx-build 5.3.0 text builder does not create genindex.txt

[gknittl]

I installed sphinx from the Debian 12 repositories and ended up with sphinx-build 5.3.0

html builder successfully generates genindex.html
text builder does not generate genindex.txt. there are no errors or warnings in the build so it appears the text builder is silently ignoring :ref:genindex and/or :ref:modindex

My use case is personal documentation that I primarily want to edit (in Kakoune). I would like to open a genindex.txt, select an index entry in genindex.txt then open the corresponding rst file for further editing. Kakoune is plenty programmable so I'm confident Kakoune can open the .rst file if Sphinx can build a genindex.txt. It would be an added bonus if I could customize the genindex.txt entry to point to the source .rst file instead of or in addition to the built .txt file

I could convert genindex.html to text, e.g. lynx -dump -list_inline but that's a bit unfriendly to read as well as a more complicated build.

[gknittl]

It looks to me that the relevant text builder source code is in sphinx/writers/text.py and that code is skipping index items among many other things. Am I missing some text builder function elsewhere? Is there a deliberate design choice to keep the text builder as bare bones as possible? If I could figure out how to make the text builder emit an index would Sphinx accept a patch? how about maintaining it? Or would it be better to write an extension? Perhaps this is overkill. my needs are so simple I can build my own index with basic text tools like grep...