Notifications live in two places. The Notifications item in the sidebar carries an unread count on every screen and every device, and it is the one to rely on. There is also a bell in the top right of your Dashboard on wider screens.
The bell shows your six most recent notifications with a one-line preview and a count of how many are unread. Click one to mark it read and follow it through. Mark all read clears the count without leaving the dropdown, and the footer opens the full page.
The Notifications page at /notifications groups everything by Today, Yesterday, and Earlier. Filter pills across the top narrow to Image, Video, Script, or Packet activity, and a pill only appears once it has something in it. Mark all read and Clear all sit in the page header.
The bell and the page are the same data, so marking something read in one is immediately reflected in the other.