The .zip-file that contains the offline version of kn Secrets can be downloaded here.
To verify that the .zip-file is genuine, use any appropriate tool to compute its SHA256 hash value. The SHA256 hash value should come out to be
9777ed762608b152788c580203b8d09552d3b817e9961855e9be75a6e9033239.
Once successfully verified, unzip the file into a directory on your disk, find the file "index.html" in that directory, and double-click that file to start kn Secrets in offline mode. Please follow the security guidelines whenever using kn Secrets in offline mode.