Existing feeds (for sites with redirect rules) stop working until manually edited to use https://
Could just be craigslist, as that's the only site I am subscribed to which is affected by HTTPS Everywhere rules, but I noticed that (since installing the extension) I no longer received notifications of updates to craigslist feeds. I had to manually edit the URLs for those subscriptions in Firefox in order to get the updates.
To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information