Because this information is critical to your security, Firefox deletes it to protect you when your password is reset to prevent other people from accessing it.
Imi talɣut-a tlaq aṭas i tɣellist-ik, Firefox ad tt-yekkes akken ad k-immesten ticki awal-ik uffir ad yalse awennez akken ad isewḥel imdanen-nniḍen ur keččmen ara.