[brokenmachine]

But almost every RSS reader has this feature.

I use FreshRSS and you just put all the feeds in one category and then you can click on that category to show all the feeds together.

[saulpw]

The reader has to add every RSS feed. What if I as the producer of those feeds want to ship a combined feed so they don't have to do that extra work? Or what if I'm a curator of RSS feeds and want to release one combined "low-tech computer news" feed sourced from 100 smaller low-tech computer news feeds?

[rakoo]

This is already solved with dynamic opml, which freshrss implements