Tested on about 20 html proxies verified as good by charon and verified able to connect to outside pages. DOES NOT WORK. Used more than one browser for testing.
Returns error cannot connect to tunnel or simlar.
Author lists his email address but if you try to email him your email is returned as a spam message and no reply More junk from Mozzila.

Самое простое и удобное в использовании. Работает отлично и ничего лишнего

This is what I use. It's very good. The only things I'm lacking is country info and some marking of last used proxy. Is it possible to add this? Can I do it myself? (Not sure it's easy because never did it)

This is the only proxy manager I found, that I can easily switch different manual proxies, when I work in office/home.