Where is my data for Chrome extension 'OneTab'?

On the Mac, the location is now in a database file located in your users folder:

~/Library/Application Support/Google/Chrome/Profile 1/Local Storage/leveldb/ files here...

I am not sure if all the files here are dedicated to OneTab, but restoring the whole folder worked for me. You may need to check for other Profile folders, or perhaps the default instead of my "Profile 1" folder. A shortcut to the folder, open terminal and execute the command:

open ~/Library/Application\ Support/Google/Chrome/Profile\ 1/Local\ Storage/leveldb/

Your OneTab data can be found at C:/Users/<Username>/AppData/Local/Google/Chrome/User Data/Default/Local Storage/leveldb. Just replace <Username> with your user's username.

I also created a Python script to automatically back up your OneTab data.

https://github.com/itsjoshthedeveloper/backupOneTab

More information found in the link above.

On (Linux Mint) Linux, the path to the OneTab data folder appears to be:

/home/<user>/.config/chromium/Default/Local Extension Settings/chphlpgkkbolifaimnlloiipkdnihall

or

/home/<user>/.config/google-chrome/Default/Local Extension Settings/chphlpgkkbolifaimnlloiipkdnihall

Copying this folder from Chromium to Chrome (after Chromium access to the Chrome sync API was recently disabled) adds all the titles and options associated with OneTab links.

This seems to be the latest place where the files are located:

C:\Users\yourname\AppData\Local\Google\Chrome\User Data\Default\Extensions\chphlpgkkbolifaimnlloiipkdnihall

It looks like the path has changed since then.

Now, the localstorage file resides in ~/Library/Application Support/Chromium/Default/Local Storage (on Mac, but it's easy to guess the equivalent on Windows).