把 Options > Privacy & Security > Firefox Data Collection and Use > Allow Firefox to send technical and interaction data to Mozilla > Allow Firefox to install and run studies 打開後, 再去把 Addon 的畫面打開, 過一陣子官方 hotfix 就會自動下載套用到 Firefox 然後 addon 就會全部回來了 (或是查看 Lagacy or unsupported addon 區). 之後再把上面那個設定關掉就行.