Someone asked this question in the past, but the answer is no longer valid. There is nothing on my system at /System/Library/dyld/
.
Here is a command that inspects the Mail.app binary and lists the libraries it uses.
% otool -L /System/Applications/Mail.app/Contents/MacOS/Mail
...
/usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0)
...
/System/Library/Frameworks/AppKit.framework/Versions/C/AppKit (compatibility version 45.0.0, current version 2299.40.116)
...
But neither of those libraries are at the given path. Where are they?
% ls /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit
ls: /System/Library/Frameworks/AppKit.framework/Versions/C/AppKit: No such file or directory
% ls /usr/lib/libobjc.A.dylib
ls: /usr/lib/libobjc.A.dylib: No such file or directory