...manual removal of the content that matches these criteria by moderators maybe?

I think we can trust moderators to manually remove content far beyond these very narrow criteria. For example there's the spam or offensive aspects.

I agree. I didn't mean it as a limiting step but rather as a gentle push to delete even more. There are questions that would fullfill your criteria (for example those linked in the question) that are still shown. Moderators can already remove (or hide) questions, I hope?

Regardless of any general mechanism or rules, each community is free to decide on its own what content should be deleted. When there's a community consensus, people could flag for mods to delete until there's something better. Anybody can flag, so we don't have to place the whole curation burden on moderators.

Monica Cellio‭ Each community should rather decide what kind of content is on-topic/off-topic. We can have general rules for post deletion across the whole network without disrupting specific community rules. Generally: if something was closed, it was either a duplicate or it was found off-topic at the community where it was posted.

Monica Cellio‭ "We can have general rules for post deletion across the whole network without disrupting specific community rules." Maybe this was already discussed somewhere else or could be its own Q&A but I'm not sure I understand how the interplay of this Meta and the metas of all communities is supposed to work. Is it something like opt-in/opt-out? Would I have to post this Q&A in all communities (I probably wouldn't do it)? If all the sub communities are kind of autonomous, does it still make sense to discuss things here on meta.CD?

Monica Cellio‭ No, communities decide what gets closed and the bot cleans up closed post after a certain network-wide criteria. Off-topic posts for example aren't useful on any of the sites, so there's no reason why closed off-topic posts would be treated differently.

Trilarion‭ there are certain things the make sense to be on global meta since they affect every site, mainly feature requests for, bugs in, and questions about the Codidact software itself (qpixel), and support for questions about the Codidact organization. Those wouldn't make sense to ask about on individual communities.

Trilarion‭ I meant that any community can decide, via discussion on its meta, that such-and-such types of posts (whatever applies there) should be deleted, and they could implement that independently of anything else we do. I.e. they don't need an automated system, though automation would make it easier if the criteria can be specified suitably. I was just offering another option since we don't yet have automation.

I also agree with Lundin‭'s approach: communities should decide what's off-topic, with the assumption that off-topic posts can/will be deleted.

Monica Cellio‭ Okay, so until this feature here is implemented, if I encounter a question that may be not useful (and is closed and not a duplicate), should I (a) flag for moderator attention and request deletion or (b) do nothing because moderators would have deleted it already if they agree or (c) start discussions on the respective meta about it?

Trilarion‭ if the community already has a meta consensus about that type of question, please flag to ask a moderator to delete it. (If there's any context the mod might need to make that connection, best to mention it. Like, if a science community had a rule against certain types of sources, mentioning the bad source would be good.) If the community doesn't already have a meta consensus, it's better to start a meta discussion to try to arrive at one. Don't do (b); it's possible mods just didn't see it.