ChessSkins does not collect, store, transmit, sell, or share any user data. Period.

No analytics or tracking of any kind.
No network requests. All artwork and code ship inside the extension package; nothing is fetched from remote servers.
No page data. The content script only injects a stylesheet on lichess and chess.com pages; it does not read page content, game data, or personal information.
Local settings only. Your selected skin and on/off preference are saved with chrome.storage.sync, which lives in your browser profile (and syncs between your own devices if you use Chrome sync). A custom skin you create is saved with chrome.storage.local on your machine. Uninstalling the extension removes both.
Questions? Open an issue at https://github.com/NikAgs/ChessSkins/issues.