This is really bad. I cannot undo or remove “never” sites.
For Firefox, Windows user, the data is in C:\Users\[your username]\AppData\Roaming\Mozilla\Firefox\Profiles\[your firefox profile]\storage\default\moz-extension+++f0d6891d-57d6-4341-a27c-8bffc1001bb6^userContextId=4294967295\idb. And the file is 3647222921wleabcEoxlt-eengsairo.sqlite
Open with Sqlite editor such as Sqlite browser, SQLiteStudio
It is in table:
0ofwfsEpnbjot, and the never list is in data column but as blob (hex). If anyone can help us about how to edit this thing then please describe.