It requests too much permissions (https://addons.mozilla.org/cs/firefox/addon/fast-image-research/ requests less). Can NOT find link to open source platform like a Github.

The way of fix in the comment is really useful，once again:

Just replace in settings:
http://www.google.com/searchbyimage
to
https://lens.google.com/uploadbyurl
,and
image_url=::$URL:: to url=::$URL::

This extention can read your usernames and passwords from websites you visit! AVOID!!

makes it easier for me to search any anime-related images

It´s not privacy friendly at all.

Зачем аддону, который ищет картинки знать пароли от всех сайтов?