I created a Safari extension which I am just calling Hashed for Safari (zip). At this point it seems to work fine but has a major limitation that it is not at all easy to use multiple secret passwords. I don’t know how many PwdHash users use multiple secret passwords but I know it affects me so I’ll be hoping to improve that in a future release.
The source is available on GitHub if you want to improve it. Keep in mind though that any changes need to keep the secret password secure from the site you are on. You can also create issues if you come across any bugs or wish to make a feature request