As I updated the version to 1.4.0 , adding the 'import' feature I am sharing this here.

I made this extension because I couldn't find one that wouldn't ask for too much permissions (such as accessing all websites data).

Eventually I found it nice to have a TOTP that can really be audited, the code is 649 lines of JS, 214 CSS and 52 HTML. Feel free to fork, copy part of it, contribute or just request fix/features.

I have used it for more than a year every day and it works nicely.