Since M$'s & Google's extension store team are unable to read or actually review the extension, have a short description regarding privacy:
The extension has permissions for, among other things, websites and your clipboard, meaning it has access to everything you access, and it will then happily do conversions you tell it to on the selected data on websites, but always in the context of your browser. The extension itself will not transmit any data to the author nor does the author intent to collect any personal data. M$ may or may not collect your data when installing or using the extension in Edge, Chrome, Opera or any other browser that can install this extension.