Browser kernel
The underlying browser engine build that a profile runs on, which determines its real version, feature support, user agent, and client hints.
In antidetect and multi-profile browsers, the kernel is the actual browser engine build a profile launches: a specific Chromium version with its rendering engine, JavaScript engine, and feature set. The kernel version determines what the browser genuinely is, including which web APIs exist, how CSS renders, and what the authentic user agent and client hint values are. Vendors maintain multiple kernel versions so profiles can run on different engine generations.
Kernels matter because version claims are verifiable. A browser can assert any version in its user agent, but detection scripts probe actual engine behavior: the presence of newly shipped APIs, version-specific quirks, and client hint values generated by the engine itself. The reliable way to present a particular Chrome version is to run that Chrome version. Pinned kernels also serve QA directly, letting teams reproduce issues on the exact engine a user reported them on.
Oculr maintains 20+ pinned Chromium kernel versions, from Chrome 86 to the current majors, with new Chrome majors ported as they ship. Each profile pins to an exact version, and its UA string, client hint brands, and feature flags derive from that version through a registry, so claims always match the real engine underneath. Kernels are managed in-app: see what is installed, install what you need.
