seems, that just category/PN is remembered here in my firefox, therefore new revision bumps are shown as read althought they are new (and unread).
Firefox seems to follow the strategy of matching the linked URL of the atom entries to your browser history. This is suboptimal and completely disregards the entry ID that we uniquely set for revisions. We don't have a URL for specific package versions, I'd rather avoid introducing any workarounds for a single client; all other news readers I know of do this correctly with the post ID.