Don't use anything 3rd party tools when it comes to crypto. It's probably a scam to steal your private keys or something.
Edit: even if the extension is not connecting to a server to send data, they can change that anytime silently buy pushing an update through the store. You can edit the extension manifest to disable updates but if you can do that then you can also use copy paste and/or a text file to keep track of your public addresses.
Why we would bother ourselves to download these extensions or 3rd party app if we can simply paste and save up on notepad our public address.It would be much safer if we would had it that way.
Opening your notepad and use those pub address wont really take too much time.