Websites practice
browser fingerprinting to identify their users. This means using the information about a user’s OS, software, and connection to create a unique combination of parameters called a fingerprint. This allows websites to track the activity coming from a given device by controlling even the smallest changes in the browser fingerprint.
Octo Browser lets you stay anonymous and create multiple accounts by giving websites different fingerprints taken from real devices. The important parameter indicating the kernel version in User Agent and Client Hints headers and API is also spoofed to enhance privacy.
However, each new Chromium version always works slightly differently compared to the previous ones, and discrepancies can easily be found by a sufficiently sophisticated script, like
CreepJS.
Chromestatus.com shows what changes in the browser in each version, and websites can use these changes to check your browser version.