Some things do accumulate. That is in fact the point of Firefox Reset[1]. The support page lists "Extensions and themes, website-specific preferences, search e

Some things do accumulate. That is in fact the point of Firefox Reset[1]. The support page lists "Extensions and themes, website-specific preferences, search engines, download history, DOM storage, security settings, download actions, plugin settings, toolbar customizations, user styles and social features will be removed." [1]: https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-most-problems https://support.mozilla.org/en-US/kb/reset-firefox-easily-fi...