Ultrawidify does not access, collect or transmit any personal data.
Data stored by Ultrawidify (your settings) is stored in your computer's browser. It is not uploaded to any cloud service.
When setting default settings for a specific site (as opposed to setting default extension settings), hostname of that site (the "sitename.com" part of the URL) will be stored in your settings. Hostname is saved only when it needs to be in order to ensure the functionality you expect (e.g. to ensure extension is enabled or disabled on a given site, or that video is always stretched on that particular site). Ultrawidify does not keep track of sites you visited otherwise.
Ultrawidify requires some browser permissions in order to function. Depending on
This permission is necessary in order for aspect ratio correction to work. Ultrawidify needs to find the video in a page ("access data") in order to correct the aspect ratio.
While Ultrawidify is only really tested on a small handful of sites, it could theoretically (and in practice does with varying degrees of success) work on even the more obscure sites that I am not even aware of. Because of that, Ultrawidify requests permission for all sites (instead of just a handful, pre-determined ones).
Required for exporting extension settings. This permission is optional — you will only be asked to grant this permission if you choose to export your settings.