Other use cases of <contrib>

[Melissa37]

Current list of attributes
contrib-type Type of Contribution
corresp Corresponding Author
deceased Deceased
equal-contrib Equal Contribution

But there are other use cases, such as co-first authors.
What are other use cases?

[jats-laura]

We're seeing a lot more cases where there's a collaborative author and the full list of individuals in that collaboration is included. I've added an example of that to contributions.md.