There is this Home Assistant integration which I remember getting working. I haven't used Home Assistant in a while though, so I can't be a good resource if you need any help.

RAR isn't open source.

Wow, didn't think something like that had happened. That is a valid concern. However, it could be mitigated by disabling auto update and subscribing to the GitHub releases via RSS. Then you can either manually check for malicious commits, or if the extension is more popular, wait a bit for any bad news to come out about the update. Obviously, this isn't possible for everyone and every extension, so I can understand why people would be cautious of more extensions, but I think Libredirect is a big enough extension that you would hear about it, like the case with Nano Adblocker.

Are we forgetting Windows 2000?