Where is the language detection logic hidden in Polylang (WordPress) when you first enter the site?

Question

Internationalization and localization

Colleagues, welcome.
Who knows where the language detection logic in Polylang (WordPress) is hidden when you first enter the site? I didn't find it in the documentation.
I have a site example.com in two languages ​​- English and Russian.
The default language is English. example.com - in English.
But for some reason, when you first enter the site, it automatically redirects to example.com/ru - which is in Russian! And I don't need it.
Where can it be changed?
I suspect the plugin is catching the locale in the browser. But where it can be rewritten by handles in PHP? I also want to add my own logic depending on the user's IP.