Fallout: The Frontier, an enormous mod for Fallout: New Vegas, has been years in development and launched just last week. It has now been taken offline by its own creators, because one developer is alleged to have "posted animated pedophillic content" on their personal artist accounts.
If you visit the mod's page on Nexus Mods, this is the message you'll see:
Some deeply concerning news has emerged in the past few hours. We have been recently notified that one of our developers, ZuTheSkunk, had posted animated pedophillic content on their personal artist accounts. The items in question are deeply disturbing to the entire team, and we condemn them in the strongest sense. ZuTheSkunk has since been removed from the Development Team and banned off of our Community Discord. We will be conducting dialogue with members of the development team to hear their thoughts regarding the current situation and help make our decision more informed. We have stopped production and work on the mod to address the current events properly. More measures will be undertaken and a more detailed address will be posted soon.
The views, thoughts, and opinions expressed both in the mod, and outside of it, belong solely to the authors who write them, and not to the mod's organization, community, or other group or individual.
I'm not sure how "the mod's organization" and any "group or individual" can claim to be completely unaware of the work "in the mod" made by their fellow groups and individuals. This is important, because prior to it being taken offline, there had already been criticism of the mod's content.
In particular, players had complained about fetishised characters, and one particular quest line through which the player could enslave a teenage girl. Slavery has been a theme in lots of official Fallout games, but there is a difference between depicting it and allowing players to revel in it, as The Frontier seems to.
On Twitter, the mod's official account said reiterated their statement above and added, "We will be making changes to the Frontier going forward to remove inappropriate lines and content. This will be our final build." It's not yet known exactly what content will be removed - nor is it clear that ZuTheSkunk had anything to do with the creation of said content.