Matrix vocabulary HOW TO: Add a matrix to the vocabulary Open a new 'addition request' issue and specify all details. Create a pull request that adds all the approved details to the data/data.yml and adds the new term to the changelog. HOW TO: Request a modification to an existing matrix in the vocabulary Open a new 'modify term' issue and specify all details. Create a pull request that adds the approved details to the data/data.yml and indicates the term as modified in the changelog. HOW TO: Request the deprecation of an existing matrix in the vocabulary Open a new 'deprecate term' issue and specify all details. Create a pull request that indicates indicates the deprecation of the term in the changelog in and removes the term from data/data.yml