CTparental: Linux Parental Control Software With Category-Based Website Filtering, Computer Usage Limits
CTparental is a free and open-source parental control software for Linux. It helps parents control their children's online activities, such as the websites they visit, and the amount of time they spend on the computer.
The tool uses a web UI to control its various settings, and it features blacklist / whitelist website filtering, computer access time, the ability to force safesearch for websites such as Google, YouTube, DuckDuckGo and Bing, and more.