I missed that part, but indeed is looking for a kamctlrc in the same folder as kamctl. Digging in memory, the actual purpose for it is to allow running/operating kamailio from source directory (just compile, not install), which is convenient when developing. That's also why loadmodule looks not only for `modulename.so` file in `mpath` folders, but also for `modulename/modulename.so`.
If you are in kamailio sources folder, you can run `./utils/kamct/kamctl` and then, as running in a devel environment, the latest `kamctlrc` of the source tree is expected to be the base config. However, the order can be changed, if most of the people find it differently to be more natural. Practically the scope it is to have a base config and a way for each user to amend only specific options, not to have full a config again.
Usually is expected to have the default config as deployed by install (in /etc/ or /usr/local/etc) when running a globally deployed kamctl or by presence in source three when running a devel environment, plus user specific options (e.g., user/password for database) in a user home config.