Link - https://varunmalhotra.xyz/enhanced-github/#privacy-policy

Enhanced GitHub Chrome Extension doesn't collect/share/care about your data at all.
Asks for GitHub Access Token only for private repos and if Rate Limiting is your concern.

Permissions Required:

1. "*://*.github.com/*" - for running on github.com domain.
2. storage - for storing GitHub access token on your local system. GitHub Access token is required for private repos and for handling API rate-limiting issues.
3. webRequest - to support GitHub being a single-page-application now.
4. webNavigation - to support GitHub being a single-page-application now.

Read the detailed blog which explains why the above-mentioned permissions are required to support the GitHub SPA website.