Extension integrity protections are the browser checks that help ensure an extension is genuine, unmodified, and allowed to run. In Chromium-based browsers, these checks can include validation of installation sources, package integrity, policy state, signatures, and whether an extension matches what the browser expects to trust. Their goal is to stop tampered or unauthorized extensions from being treated like legitimate browser components.
These protections matter because extensions often have broad access to web pages, credentials, and user activity. If an attacker can bypass integrity checks, a malicious add-on may blend into normal browsing and persist inside the browser profile. Defenders use these controls in managed allowlists, policy enforcement, and extension inventory reviews to reduce risk. In attacks, failures here often show up as sideloaded, repackaged, or policy-abused extensions that appear approved even though they are not.