There's a fork of the repo you posted: https://github.com/QuanZhang-William/gemini-cli-security that's listed on Google's extensions gallery page: https://geminicli.com/extensions/browse/
EDIT:
I've posted about it on GitHub: https://github.com/gemini-cli-extensions/security/issues/81
Hopefully the relevant team will see it there.
Hey! I'm the PM for that extension — thanks for sharing it. Give it a try and let us know what you think about it.
Feedback, bug reports, and ideas are all welcome on the GitHub repo's issues tab. Happy to answer any questions here too.
This one seems to showcase a bunch of the "extension" features, including a custom MCP for dealing with file line numbers.