Hi zyl456,
thanks for your rating. As from what I read, in your option the edge (quit zone) of the QR code is too big and saving the QR code image is too cumbersome.

First of all, let me explain that the whitespace around the QR code is important from a technical point of view for most QR code readers to properly recognize the QR code. See https://github.com/rugk/offline-qr-code/wiki/FAQ-(chinese)#%E4%BB%80%E9%BA%BC%E6%98%AF%E5%AE%89%E7%A9%A9%E5%8D%80 (or https://github.com/rugk/offline-qr-code/wiki/FAQ#what-is-a-quiet-zone in English) for more information.
Secondly, for design reasons AFAIK some more space is kept.

When saving the code as an image, we offer two variants. That is as SVG or PNG. See https://github.com/rugk/offline-qr-code/wiki/FAQ-(chinese)#%E5%A6%82%E4%BD%95%E5%B0%87-qr-%E7%A2%BC%E5%84%B2%E5%AD%98%E5%88%B0%E7%A3%81%E7%A2%9F%E4%B8%AD (or https://github.com/rugk/offline-qr-code/wiki/FAQ#how-to-save-the-qr-code-on-disk in English) In order to convert the image into the proper format, there are two context menu entries. Unfortunately, once you use more than one entry, Firefox automatically makes this a sub-menu, so there is nothing we can do there.
The permission is requested, because this is the only way to show a "Save file" dialog, where you can choose where to save the file. It should only be requested once and if you have approved that optional permission, there is should not need to do that again. It is an optional permission to keep the number of permissions low especially as not all users may use this feature.
See https://github.com/rugk/offline-qr-code/blob/master/assets/texts/zh-CN/permissions.md (or https://github.com/rugk/offline-qr-code/blob/master/assets/texts/en/permissions.md in English) for more information about the permissions this add-on requests.

If this helps, it would be glad if you could adjust your voting.

If you have further issues or questions, feel free to ask or suggest a feature by opening an issue on https://github.com/rugk/offline-qr-code/. Thanks.

Best regards
rugk