Lemmy Support

It depends on the instance rules and admins. On lemmy.ml:

1. Nothing happens at the moment the last mod goes AWOL. The community muddles along without a moderator for a while.
2. It's not clear to me what happens to reports during this period. I expect admins have some way to see them, but it's not clear how visible they are or whether admins take action on them.
3. When a new mod wants to take over, they post in https://lemmy.ml/c/community_requests with a description of why they think the community is unmoderated and a request to take it over.

I think you can try to get in touch with the administrator of the community's instance and propose yourself or someone as new administrator of that community

Every instance has to have an administrator or the instance can't exist. A community does not have to have a moderator since it only requires an instance. So if there's no mods for a community, the admin of the community's instance can either leave it unmoderated, do it himself, or find a new moderator.

If want to help grow a community and it has no moderator, you could ask the admin to volunteer. I mean volunteers are what open source and community is all about.

What happens when a community in Lemmy is left without a moderator?

Each person who has posted in that community in the last year must join in group ritualistic combat with each other. The venue, type of combat, and weapons are decided based upon the topic of the community. So quite easy for communities about knife making or baseball, and somewhat murkier for communities about etymology. The first person to lose in combat and the last person standing are indentured into permanent moderation duties. The instance administrator referees and judges the event.