It’s been 10 days for at least a week now, but it seemed I missed the site feedback category (and some sub-categories), sorry about that. I’ve done some analysis of gtk-devel, and it looks like for the entire last 12 months, only two emails would have been more than 10 days since the last reply. Would 14 days make sense perhaps?
Hrm, this is odd. The re-opening counts as a ‘reply’, so it should have had the longer period. I did recently add the ‘solved’ button which allows the original poster to mark a reply as having solved their issue. I wonder if that automatically closes the topic… I’ll have a look at that.
Moderators and admins can split a topic if it’s becoming off-topic, but I think this is a different thing to auto closing threads. That’s there to prevent thread necromancy. If there’s a topic that is closed, you can always message a moderator asking for something to be re-opened.