If there is one (and only one) saved block/allow setting in XSS choices (Advanced Settings), it is not possible to remove it.

Selecting it and clicking on the delete button does remove it from the interface, but the change does not take effect. If the site in the choice is visited, the saved XSS choice is still applied. Moreover, reloading the settings page shows that the setting has not been removed and is still present.

It seems to be impossible to remove the choice by using the 'Debug' option at the bottom of the page, as XSS choices do not apparently appear there.

The only option seems to be exporting all settings, modifying the exported file, changing the "xssUserChoices" to an empty object, and re-importing the settings. The "xssUserChoices" must be present and set to {} in the imported file; if it is not present, existing XSS choices are apparently not removed.

Using NoScript 11.4.37 on Firefox 115.15.0 ESR on Debian GNU/Linux.