TL;DR: I built this to link series review podcast episodes as alternate audio tracks next to the corresponding Sonarr video file in the library. That’s not the main goal, so it’s only marginally related to Sonarr, but I hope it’s of interest to some here.
$ feed-archiver command aims to archive RSS/Atom feeds as fully as possible in such a way that the archive can serve (at least) 2 use cases:
A mirror of the archived feeds that can be in turn served onto onto feed clients/subscribers (such as podcatchers). For example, you can subscribe to the archived feed from your podcatcher app on your phone with auto-download and auto-delete of podcast episodes while archiving those same episodes on your HTPC server with large enough storage to keep all episodes. The archived version of the feed will also reflect the earliest form of feed XML, item XML, enclosures, and assets that the archive downloaded and as such can be used to reflect the original version to clients even as the remote feed changes over time.
An alternate hierarchy of feed item enclosures better suited for ingestion into other media software, such as media library servers. For example, your podcast episodes can also be made available in your Jellyfin/Emby/Plex library.