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I assume they mean pair programming [1], user stories which are used in agile methodologies [2], and test-driven development [3].

I interpret that as:

Pairing - Pair programming, which if one of the developers has experience with the product will solve questions that you otherwise will solve with docs.

Comprehensive User Stories - User story like in Agile/Scrum, where it has an acceptance criteria, goals, description, etc. and can be used to track back documentation of features.

Tests - User test cases, which can be a replacement of the documentation of how to use the product or the intent of the features.

Sorry, that could have been clearer. I meant the practice of pair programming, including user stories in Jira tickets (to explain why the ticket exists in the first place) and tests for your codebase to help others understand how the code operates.