Ask HN: Where do you keep your error code glossary

We need somewhere to keep a list of our app's error codes, so that:

- we have a single source of truth

- we don't repeat/overlap by mistake

- human readable to reduce collisions, low barrier to find

- is machine readable so can be used for i18n, etc

- can be used to publish something like this: https://www.twilio.com/docs/api/errors

Looking for suggestions of where to keep this list. Confluence makes the last two hard. A file in git isn't so findable. Have you done this on your projects? Where would you keep this list and why?