Wikipedia:Attribution does not require blame

Wikipedia's licensing requires that attribution be given to all users involved in creating and altering the content of a page. Wikipedia's page history functionality lists all edits made to a page and all users who made these changes, but administrative deletion actions may remove or hide some of this information. A list of authors satisfies the attribution requirements without providing the specific contributions.

Glossary

 * Attribution is the credit that a contributor receives, required by the Wikimedia Foundation's Terms of Use, section 7. Licensing of Content. It should not be confused with attribution of sources as covered by Attribution.
 * Blame is a user's precise contribution, the individual diff in the page history. The term is a tongue-in-cheek reference to the WikiBlame tool and the  command.

List of authors
The Wikimedia Foundation's Terms of Use, section 7.b.iii, specifies a list of authors as a valid attribution method:

"Through a list of all authors (but please note that any list of authors may be filtered to exclude very small or irrelevant contributions)."

clarifies its use in practice.

A list of authors does not include page content and cannot provide blame. Therefore, the licensing requirements do not include blame. In January 2022, via email with a Wikipedia administrator, Wikimedia Foundation Legal shared their perspective reaching the same conclusion.

Page deletion
Deleted pages may be restored if their content is non-problematic and desired for reuse, but there are alternative methods described in. Since deleted revisions are not publicly visible, attribution is provided by a list of usernames. When such a list is a separate page, it is tagged with Attribution history, which includes it in Category:Pages used to preserve attribution.

Selective deletion is a copyright cleanup technique that has been superseded by revision deletion. It involves deleting the page and restoring specific revisions, so it uses these attribution methods.

Revision deletion
When using Revision deletion and deselecting the Delete editor's username or IP option, usernames are not deleted. They remain visible in the history, which still functions as a list of authors. This is the setting generally used, including with the RD1 copyright criterion.



Username hiding (copyright attribution issues)
 * Wikipedia's licenses require that accessible edits be linked to the user who performed them, so it is generally a problem to hide the username from a revision while leaving their edited changes to the page in public view.
 * Cases where it is acceptable are:
 * The revision contains no valid information copyrightable to the user who posted it (e.g. plagiarism, gibberish, vandalism, adding categories, no copyrightable change made to revision text, etc.); or
 * All copyrightable changes have been reverted and the text of all intervening revisions has been hidden; or
 * The user accidentally posted while being "logged out" and the aim is protection of privacy at the request of the user.



"Hiding of a username or IP should only be used where that username or IP has a reason in and of itself to be hidden, such as accidentally editing logged out or an attack username. Hiding a username will remove the contribution completely from the user's contributions list (except from administrators, who will see a warning indicating it is invisible to users), rather than a crossed out entry for deleted edits without hidden username. This will cause issues with users trying to review actions taken on the user, as well as potential copyright violation risks."