Sorry, I didn't get an email about this. There is no need for a "short" letter option for every long option like "--maxdepth". It could use a numeric option value as some of the other options do.
The lustreapi.h file is definitely located in the Lustre source tree, even if it is installed into the system by RPM packages. Using "git grep" is your friend to find things in the source code, if your IDE does not have tags to jump to structure and function definitions.
As for modifying the find_param struct, since this is also used as part of the user API, it should only be modified by adding new fields to the end. Some caution is needed since there are a few other patches in flight that are also modifying this struct.
"Maximilian Dilger <mdilger@whamcloud.com>" uploaded a new patch: https://review.whamcloud.com/55226
Subject:
LU-10522utils: new --mindepth for lfs findBranch: master
Current Patch Set: 5
Commit: 9df10214fb073434c6e634e5169e72aa7a606e9f