Uses external service for QR code generation (this fact is not stated in add-on description). Not safe. Especially, considering there are self-contained (offline) alternatives.

Fa esattamente quello che dice: qr code in modo semplice. Volendo, si può anche ridimensionare.

I have found another service that can generate QR code, and the provider guarenteed that "Your QR code data is encrypted during transmission (TLS/SSL) and not stored":
http://goqr.me/api/
Is it possible to integrate into your extension?

Very handy addon, which does everything one would need to generate QR code from any text or link on the page. Not limited to page adress. 5 stars from me.

Good

While it's working well, the following points have to be fixed:
• published under GPL3.0 but no link to check the source code
• no release note with the last update
• no link for support

URL-page to QR Code is not working.
Does encode a selected text.

Dobre, jak dla mnie bomba.

This extension uses the google charts API to generate the QR code, meaning it's NOT self-contained and effectively "leaks" the URL to google whenever you use it.
This isn't bad by itself, except that the title being "JavaScript" can be easily interpreted (such as was my first thought) to be purely done in javascript without performing external web requests to 3rdparty services.
It is a nice lightweight extension regardless, but I can't rate it too high due to this.