When you are about to delete a page (?action=delete), the form is prefilled with auto-generated edit summary.
The edit summary typically reads:
content was: "Excerpt from the page content", and the only contributor was "[[Special:Contributions/MediaWiki default|MediaWiki default]]" ([[User talk:MediaWiki default|talk]])
This summary is problematic and should be removed from core.
- It leaks content that was deleted. Because this summary persists in the logs even if the whole revisions were later revision-deleted/or page deleted; the excerpt remain indefinitely accessible to unprivileged users.
- The summary generates false contributor if the preceding revision is suppressed. Attributing attack/offensive content to other users is quite problematic (T24999: Article::generateReason returns wrong result when all users except one are hidden idling five years, unfixed)
- The generated summary is redundant to the other preset dropdown summaries, other actions (protect, move, etc ) just reserve this field for additional manual input should admins want use it, and that's the very essence of the field as its name suggests: It's called "Other/additional reason" NOT "automatically generated reason."
- It disrupts workflow. Because the content is auto-filled, if an admin wants add additional reason, they have to first delete this prefilled content; an unnecessary work. (When deleting attack/defamatory pages, not deleting this summary leads to problem no. 1; and most admins are not aware of this. Nowhere hint of this possibility can be found.)
- Offensive page creation edit summary cannot be hidden (except with suppression, a high-level permission whith more restrictive policy, so not appropriate for most cases ). Even if admin revision-deletes the specific edit summary, this autogenerated summary paradoxically remains indefinitely in the page creation log for all users. (T230425: Page creation log should not display the content of deleted pages)
- Creates inconsistency with other action pages. None of them generate automatic edit summary, even if they have similar field (cf. ?action=protect)
- Generates meaningless summary if blanking precedes null revision before deletion. (T55998: exbeforeblank autosummary should check the last non-empty revision)
- (Probably other issues)
Remove it. Let admins use the field as they just do in all other action pages where this field exists.
This aligns it more to the other action pages.
It will also stop this leaking of [revision]deleted content. AFAIK, this is the only place where revdeleted content is currently accessible by those without the necessary permissions.