Reproduction steps:
1. Create a new project
2. Open Preferences > Asset Pipeline
3. Click "Learn more..." next to "Import Worker Count %"

Expected result: A page with relevant information is opened
Actual result: A missing page is opened (https://docs.unity3d.com/Manual/ParallelImport.html)

Reproducible with: 2021.2.2f1, 2022.1.0a15
Could not test with: 2019.4.32f1, 2020.3.22f1 (no Asset Pipeline in Preferences)

Notes:
1. The link is correct but the documentation isn't implemented
2. The implemented page exists in the Japanese documentation: https://docs.unity.cn/2021.2/Documentation/Manual/ParallelImport.html