Youtube subscription unread tracker is a free Chrome add-on developed by neworld. This add-on helps users track new content in their YouTube subscription page. It is particularly useful for those who use subscriptions to add new videos to their "watch later" list.

Unlike other plugins, this add-on does not use the YouTube API to hide videos. Instead, it works by marking videos as read based on timestamps, rather than their actual presence in the list. This allows for synchronization of read videos between different browsers.

However, there are a few quirks with this add-on. Sometimes, the plugin may not recognize the page, but a simple page refresh should resolve this issue. Additionally, the add-on uses approximately 10 videos as markers to distinguish between new and old content. If subscriptions are removed, all marked videos may be lost, causing the plugin to display all videos as new. Similarly, if new channels are subscribed to, all older videos from these channels will be marked as read.

Overall, Youtube subscription unread tracker is a helpful tool for users looking to keep track of new content in their YouTube subscription page. Its unique approach to marking videos as read sets it apart from other plugins in this category.