Malware protection
Yandex Browser for Mobile checks downloaded files for viruses and blocks pages with malicious software.
Blocking dangerous pages
When you open a web page, Yandex Browser checks it against its database of infected sites. If the page is found in the database, it won't load. The screen will display a notification and the icon 
will appear in the SmartBox. You can nevertheless choose to ignore the warning and visit a website with dangerous content.
Checking downloaded files for viruses
Downloaded files may contain malicious code. This is why the browser scans all archives and executable files that are downloaded both directly and in the background.
If a downloaded file contains a malicious program, the browser warns you and offers to delete the file.
Blocking mining scripts
Mining is often used for issuing cryptocurrencies, such as Bitcoin. The computer makes calculations and its owner is awarded a certain amount of cryptocurrency.
In the case of hidden mining, the miners use the resources of other people's computers and mobile devices to make the calculations. The mining code might be hidden in JavaScript on website pages. This code can't be called malicious in the classical sense of the word, but it uses a lot of RAM, consumes battery power and heats the tablet up.
To prevent miners from using your tablet, Yandex Browser for mobile blocks mining scripts and prevents their downloading from sites. Scripts can be blocked even if they are yet unknown to the browser. The browser analyzes the CPU load generated by sites and uses this data to block previously unknown mining scripts.
If you want to stop blocking mining scripts, disable ad filters in the browser.