Question about Support for MSVC's format ARM64X in LLD

We would like to add support for ARM64X in LLD (i.e. allowing LLD to perform LTO on LLVM bitcode and then letting MSVC’s link.exe perform the final link with the final regular objects)

The input to LLD would be two versions of the same object: one for ARM64 and the other for ARM64EC plus any libraries we are linking with. In the case we care about, LTO, the objects would actually be LLVM bitcode. Since I’m new to LLD development, where do you think I should start to implement this?