Actually, this add-on has ALWAYS needed and requested the "< all_urls >" permission in order to modify requests to websites. That is *not* new, but probably you have become more security-conscious since you originally installed it. We should all be careful, and there is a support article on this: https://support.mozilla.org/kb/tips-assessing-safety-extension

If anyone prefers to install the previous version, you can grab it from the All Versions page at: https://addons.mozilla.org/firefox/addon/dont-accept-webp/versions/

(What *is* new in version 0.9 is checking whether you have another add-on known to have a conflict with this one.)

For what it's worth, I still have no interest whatsoever in what you are doing in your Firefox, and there's no way for me to know because this add-on still doesn't send me any data. If you don't believe me, then don't use the add-on.