Avito фильтр (+OLX) is a free Chrome extension developed by Алексей Попов. It falls under the category of Browsers and subcategory of Add-ons & Tools. This extension allows users to filter out viewed or unwanted ads on the Avito.ru and Olx.ua classifieds websites.

Using the extension is incredibly simple. All new ads are marked with an aquamarine color, indicating that they have appeared after the last page update. Any ad can be hidden by clicking on the cross icon.

Hidden ads can be viewed and restored if desired. To do this, there is a hidden menu located at the right edge of the window, denoted by two horizontal arrows (see the first screenshot). In this menu, click on the "Показать скрытые" (Show hidden) button, and all hidden ads (highlighted in sandy color) can be viewed. Clicking the "OK" button will restore them to the unhidden state.

The "Наблюдение" (Observation) feature is available for tracking new ads. Instead of manually refreshing the page to check for new ads, users can enable this feature from the menu. The page will automatically refresh every 30 seconds and play a sound notification when a new ad appears, after which it will disable itself.

Overall, Avito фильтр (+OLX) is a useful Chrome extension for filtering ads on Avito.ru and Olx.ua. It offers simple and intuitive features to enhance the user experience while browsing classifieds websites.