Converting Mailchimp Newsletters to RSS Feeds

I recently read Josh Müller's post on subscribing to Mailchimp newsletters with RSS. I was inspired to make a utility, similar to my Duck Address Composer utility, that makes it as simple as pasting a URL to subscribe with RSS.

As far as I can tell, every Mailchimp email list has a corresponding RSS feed associated with it. It's not always easy to find, but it seems like it's always there… even if you need to dig a little bit for it.

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There are 3 pieces we need in order to find this list’s RSS feed, and all of them we can find in this URL:

1. us11 - This appears to be the Mailchimp server location associated with the mailing list's account
2. u=00722345fc94fb4d4b323edc3 - I think this is a user identification code? Not sure. We need it, though!
3. id=4ff553ba3e - Again, not 100% sure what this is; possibly a list id? We need it too, regardless ¯_(ツ)_/¯

My creatively-named Mailchimp RSS utility converts the list-manage.com profile and subscribe URLs to a campaign-archive.com feed URL by following Josh's instructions.