Privacy Policy
Last updated: 2026-08-05
CrosTem — the browser extension and the Mac app — shows Mac compatibility information for games while you browse Steam. Both are developed by Sacha Gennari (s2c52).
The short version
CrosTem collects no personal data whatsoever. There is no telemetry, no analytics and no accounts, and no data ever leaves your machine except the anonymous requests needed to look up game compatibility.
What CrosTem does with data
- No collection. CrosTem has no servers. Nothing you do is recorded, transmitted or sold — to us or to anyone.
- Local storage only. Compatibility results are cached in your browser's extension storage to avoid repeating requests. Your preferences are stored in your browser's sync storage, which your browser may sync with your own browser account. You can clear both at any time from the extension's settings page.
- Match corrections. If you correct a wrong game match, that choice is stored locally. The export feature writes them to a file on your device; nothing is uploaded.
- The Mac app. Everything the desktop app stores — cache, settings, match corrections — lives in ~/Library/Application Support/CrosTem on your Mac. Its connection to Steam is localhost-only. Delete the folder and it's all gone.
Network requests CrosTem makes
To look up a game's compatibility, CrosTem requests public pages and APIs of these services, sending only the game's name or public Steam app id:
| Service | Purpose |
|---|---|
www.codeweavers.com | CrossOver compatibility ratings |
www.applegamingwiki.com | CrossOver/Parallels/Rosetta 2 status |
raw.githubusercontent.com (AreWeAntiCheatYet) | Anti-cheat support status |
store.steampowered.com | Game name and native-Mac flag (the same site you are browsing) |
These requests carry no identifiers beyond what any web request includes. Each service's own privacy policy applies to what they log server-side. Results are cached (default: 7 days) to keep requests to a minimum.
Permissions
- storage — to cache results and save your preferences locally.
- Host access to the services listed above — solely to fetch compatibility data. The extension runs on store.steampowered.com pages to display the information in place.
- The Mac app asks for no special macOS permissions. It talks to Steam over a local debugging channel that exists only for the session you enable, and only on your machine.
Affiliation
CrosTem is not affiliated with, endorsed by, or sponsored by CodeWeavers, AppleGamingWiki, AreWeAntiCheatYet, Valve/Steam, or Apple. All trademarks belong to their owners.
Changes and contact
Changes to this policy will be reflected on this page with a new date. Questions: open an issue on the project repository or contact the developer.