settings set -- target.source-map <old-path> <new-path>
settings append -- target.source-map <old-path> <new-path>
Lookup a mono symbol to find out where the source code was when Jenkins built the package
(lldb) image lookup -vn mini_init
1 match found in /Library/Frameworks/Mono.framework/Versions/Current/Commands/mono:
...
CompileUnit: id = {0xffffffff00084fd3}, file = "/Users/builder/jenkins/workspace/build-package-osx-mono/2019-02/external/bockbuild/builds/mono-x64/mono/mini/mini-runtime.c", language = "c99"
...
Set up a “source map” telling LLDB where the code really is
(lldb) settings set -- target.source-map "/Users/builder/jenkins/workspace/build-package-osx-mono/2019-02/external/bockbuild/builds/mono-x64" "/Users/work/2019-02/mono"
https://www.mono-project.com/docs/debug+profile/debug/lldb-source-map/