Taming Abstraction: Tool-led d.r.y. vs sane and readable docs source without too much duplication

What is the best balance for a docs team who has to maintain the docs and outside contributors who need to understand before they can contribute? (And are there workarounds to help reviewers who are not so familiar with Antora or your chosen tool & methodology?)

[Examples will be shown from the many Apache-licensed, public docs repos at https://github.com/couchbase/ ]