I never completed the install of this vpn, but now on many of the tabs i have open is this injected code:

<div id="rate_us">
<div class="uvpn_wrap">
<div class="uvpn_logo-ext">
<div class="uvpn_logo-wrap">
<img src="moz-extension://4a1b889f-6e45-0b4e-ae9c-94b70bb75106/img/128.png">
</div>
</div>
<div class="uvpn_title">
Don’t Forget to Rate Us
</div>
<div class="uvpn_desc">
If you enjoy with our product, give us 5 stars. It helps so much!
</div>
<a target="_blank" href="https://addons.mozilla.org/ru/firefox/addon/uvpn-unlimited-vpn/reviews/" id="rate_btn_rateus" class="uvpn_rate-btn uvpn_btn">
Rate Us
</a>
<div id="close_btn_rateus" class="uvpn_later-btn uvpn_btn">
Not Now
</div>
</div>
</div>