Hello! Can I remove an already existing Brave signing key from the /etc/apt/trusted.gpg.d? Without doing this, there’s no added security benefit. Any third-party (unofficial) repository which has its signing key added to /etc/apt/trusted.gpg or /etc/apt/trusted.gpg.d can replace any package on the system. Even if we assume none of the repo owners are malicious, an attacker might compromise a repo, which has the same end result.
If you do that, wouldn’t signature checks fail on updated packages from the Brave repo?