@InternetKevin It is indeed a great idea, but while the basic idea of decoding the document in a sandbox to a trivial and thus likely safe format is sound, a container is not a safe sandbox! And even ignoring the various container escapes that keep cropping up, requiring the user to install Docker and spawn containers in it off of Dockerhub opens them up to whole new classes of exploits. It's not clear that running this actually makes a user safer, especially from a targeted attack.
[Notice Regarding the Transfer of the mstdn.jp / mastodon.cloud Services] We have received several inquiries showing interest in a transfer following the announcement of the end of the mstdn.jp and mastodon.cloud services. As a result of subsequently evaluating the situation and making preparations, we have decided that the corresponding services will be transferred to a company in the United States on June 30. We will make an announcement regarding the name of the company that the services will be transferred to once preparations have been made. Thank you.