Rated 5 out of 5 stars
But manually archiving works good in RSS-accounts...This review is for a previous version of the add-on (0.9.1). This user has other reviews of this add-on.
(limited) archiving of RSS accounts in 0.9.2
See the new version 0.9.2. Now it can also archive RSS accounts (but with default archive settings only, because the Thunderbird aechive settings are not available for Feed accounts)