Hi, @majidheidary, I am from @SnaxTeam. Browser extension is needed to use snax.one UI to bind your social accounts to Snax and to make transactions (just a wallet functions).
All the content you create, is grabbed automatically by the oracle
the whole code of Snax extension is open sourced. We use clipboard permission to copy mnemonic phase which can be used to create an asymmetric private key. Also we use it to copy your export private key: But that’s it. https://github.com/SnaxFoundation/snax-browser-extension. You can see the same permissions for Google Docs Offline, for example

You can read more about SNAX in our whitepaper https://snax.one/whitepaper.pdf or in this review for example https://steemit.com/snaxbountyoprogram/@milaan/review-of-snax-as-a-decentralized-social-media-overlay-for-monetizing-content-with-existing-popular-social-media.