Thanks for clarifying, I was worried for a second.

Thanks for posting this!

Wonder what’s going on there

It doesn’t store media forever that is routinely cleaned and configurable in the administration settings for the instance. The content cache, which is database storage used for the text and meta-data of posts is more typically an issue over time because this requires commands to be run on the server to free up space, which many people do not do. https://fedihost.co/blog/slug/managing-mastodon-storage