I will ask for the HQ. Thanks very much.AFAIK - Karo is an electronics company who create single board computers (preloaded with Linux, Windows or Android) for industrial applications:
I believe they also do software development to create tools/applications for use with their products.
So Karo isn't a piece of software, it's a company/vendor.
adjoin-client must be a script created by Karo.
I could be wrong, but I don't think karo's software is in the Debian repos. I'd imagine their software will only be available to their customers!