Hey @Pascal258
Welcome to the MainWP community.
This indeed looks to be a false positive.
MainWP uses Automattic’s API mShots for Child Sites screenshots: GitHub - Automattic/mShots: Website Thumbnail/Snapshot Service
These screenshots are then fetched from https://s0.wp.com or https://s0.wordpress.com to be displayed in Manage Sites grid view or on the Child Site Overview page.
