I can find the previous localStorage api data in ~/.config/google-chrome/Default/Local Storage
directory. I see that these are sqlite files which I can browse w
For Windows, you can find different data related to your extension [extension_id] at these places
C:\Users\[user_name]\AppData\Local\Google\Chrome\User Data\Default\Local Extension Settings\[extension_id]
C:\Users\[user_name]\AppData\Local\Google\Chrome\User Data\Default\Sync Extension Settings\[extension_id]
C:\Users\[user_name]\AppData\Local\Google\Chrome\User Data\Default\IndexedDB\chrome-extension_[extension_id]
want to checkout chrome.storage data
type command
chrome.storage.sync.get(null, function (data) { console.info(data) });
or
chrome.storage.local.get(null, function (data) { console.info(data) });
For Firefox which now use the same format as Chrome for addon they are saved here:
C:\Users\Marc\AppData\Roaming\Mozilla\Firefox\Profiles\x5jztslz.default\browser-extension-data\