Please add the ability to create folders inside the folders.

Sorry, but why is this a recommended add-on by Firefox when the source code isn't available? Your privacy policy is meaningless. Your addon requires heft permissions and we can't see - for sure, not going by your word - what it does with them. This is not the sort of thing Mozilla should be recommending. If this is a "free" add-on, but not open-source, then users should suspect they are the product being sold, not the software.
Please provide source code. I would love to revise this review.

Finalmente, un RSS que acepte redes sociales como FB para solo recibir las notificaciones

the buttons/image links for starting the podcasts are not working. they are disabled and nowhere i can not fix that issue.
here a example page, it is for all other sites to:
https://www.tagesschau.de/inland/gesellschaft/11km-handel-kz-porzellan-100.html
i need more colors/themes and possibility to change the size of fonts.

This is simply the most essential part of my web experience, thanks.

Has all the features I'm looking for except for one:
The ability to open all new pages in new tabs and also mark them as read with one button, ideally from the button in the toolbar. Right next to "open feed reader" and "find feeds in current tab" should be "open notifications in new tabs and mark as read".

Edit: Never mind, view mode 6 has an embedded iframe of the site. This is perfect. (Would like it to be open source tho)

Feedbro is among a couple of unlimited RSS readers that I could find. The options menu provides a lot of customization for your feeds but ironically you can't automatically or easily arrange your folders alphabetically. Import and export features exist including Firefox sync option which I have not used yet because I don't know the sync size limit. Manually syncing is straightforward but it seems to accrete things instead of a snapshot in the way the file tree was arranged in the first place when saved as a OPML. Feedbro isn't great simply because no good free readers exists, it is overall well-done. However, it is not without flaws, the biggest one so far is that the extension becomes top-heavy if you add a lot of feeds and can impact browser and your overall computer performance. Those who are subscribed to a few or several feeds should not expect see large performance declines.

Das Addon ist hervorragend! Allerdings fehlt mir die Möglichkeit die "Einstellungen" zu sichern!?

I particularly enjoy the folder structuring via drag and drop. Aggregation of social media feeds is amazing. Using feedbro on Android via kiwi browser is not convenient on my mobile device - bummer. Anyway 5 stars!

genuinely just feed reader perfection. dumbass-proof!

I hope for the inclusion of multi-level folder functionality. The OPML file I imported only contains the first-level folder, while the rest of the feeds have been flattened.