Well the code there quite simple, there is not really a room for exception (especially if it works for everybody else):
DBOpenRequest.onupgradeneeded = e => {
console.log('DB: onupgradeneeded');
const db = e.target.result;
db.onerror = Errors.createDatabaseErrorHandler(chrome.i18n.getMessage('err_db_creation'), reject);
if(!db.objectStoreNames.contains(DB_IMAGE))
db.createObjectStore(DB_IMAGE, { keyPath: ['url', 'group'] });
if(!db.objectStoreNames.contains(DB_HISTORY))
db.createObjectStore(DB_HISTORY, { keyPath: 'id', autoIncrement: true });
if(!db.objectStoreNames.contains(DB_ORIGINAL))
db.createObjectStore(DB_ORIGINAL, { keyPath: ['url', 'group'] });
};
Anyway, it’s was reported by only like 0.04% users and all of them are Firefox users so I guess it’s related with some crazy old half broken Firefox profile and we are just wasting time here …