Yes, and those other paragraphs are the same thing other proprietary companies do. Your opening paragraph is just absurd on the face of it because “inspected” does not mean “by themselves”.
The second paragraph is literally speculation about something that might happen.
The third paragraph is about bug bounties, which every major software company does and which does not involve code inspection.
You just smokescreened and talked around the fact that your opening statement “it probably is inspected” is entirely unverifiable and non-credible even if true. I guess since you started that sentence with “I imagine” then it is technically true. You did imagine that.
I admittedly should’ve done more research before my first comment, but it does actually turn out that everything I said is true. Proton’s technology was previously audited by Mozilla and is currently audited by SEC Consult and other companies regularly, and the audits are available for everyone to view. Additionally, they do have a bug bounty program. Also (and this is something I didn’t mention), the ProtonVPN and Proton Mail apps are all open source.
Is that the backend code? It seems like they’re talking about the apps, not backend code. The thing being discussed here is backend code.
Nearly all of Proton’s stuff uses publicly verifiable client side encryption, so idk what all this is about