IMHO you do not need to access all sites (or "tabs"), but only YouTube. As such:

• use host permission maybe?
• or, as you actually do not need to inject anything into the site, I guess activeTab may be more than enough. 😄

Steps to reproduce

1. Go to https://www.youtube.com/channel/UCo4693Ony4slDY5hR0ny-bw/videos
2. Open … menu in search bar. (if needed)

Expected behavior

Add-on should allow me to subscribe

Actual behavior

Greyed out:

Firefox 71

Create options menu with, for now at least, option to use regular RSS subscription or to use Feedly

• Need Feedly icon
• Need to add Feedly URL handler using template https://feedly.com/i/subscription/feed/:url
• Need to implement storage (shared)

In the GitHub Readme you link to your statistics at https://addons.mozilla.org/en-US/firefox/addon/youtube-feeds/statistics/, but actually these cannot be seen there, because you did not share them. It's an opt-in in the settings.

it is disappointing that other platforms are also generating feeds, but not making them easily available to the user and as the purging and censorship at YT continues, the alternatives are becoming more relevant

please consider adding support for other platforms - you can find some format info here if needed

IMHO the red subscribe icon is a bit too much. 😉 I know I am on YouTube, so I rather only need an RSS icon.
Here you can find a style guide for a good icon color.

While SVGs work, PNGs are required for icons in AMO & in add-on list.

Add in whatever sizes are recommended

Is there any workaround to allow subscribing to channels directly from the upload pages?

Increase size of RSS inside icons

Steps to reproduce

1. Go to https://www.youtube.com/playlist?list=PLw4Vbi28NT4_UghDQpQ63R9VbR8WhzfGS
2. Click the YouTube Feeds icon

Expected behavior

All seven videos should be displayed

Actual behavior

Only displays five videos

Screenshots