EDIT: And [dead] removed now. Fascinating. I checked the unofficial guide on GitHub again to confirm my understanding:
https://github.com/minimaxir/hacker-news-undocumented#flaggi...
> A [dead] submission (that does not also show [flagged]) is killed by a moderator or by the software. They will only be shown to users who have showdead enabled in their profile. A submission can simultaneously be [flagged] and [dead].
No, it doesn't mean that. [flagged] is by users, not mods. [flagged][dead] means enough users have flagged it to kill it. [dead] alone is the result of moderator action (manual or automatic).