Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Q&A for work
Connect and share knowledge within a single location that is structured and easy to search.
I have found 61 questions searching for "equal contribution". Since, I don't have the required reputation, maybe someone else wants to add this tag.
Since we already have "authorship" as a tag, it makes sense to make "equal-authors" a synonym for authorship ("co-authors" is also a synonym). I've entered this into the tag "dictionary."