Use a utility like WinRAR, 7-Zip, or The Unarchiver. If the file is part of a multi-part archive (indicated by the -3 suffix), you may need the other parts (e.g., -1 , -2 ) in the same folder to extract it successfully.
Could you clarify or what software generated it? I can then tailor the article to be more specific to that industry or tool. task.l3mtzzcunn-3.rar
Continuous Integration (CI) tools often package error logs and screenshots into these formats after a specific test "task" fails. Use a utility like WinRAR, 7-Zip, or The Unarchiver