What are Symlink Libraries and When Do I Include Them?

I can find nothing in the docs or on this forum about the Symlink Unity libraries, other than someone saying they should NOT be included in iOS projects. Is that true? When should I check that box and when shouldn’t I? What is their purpose?

I guess I’m not the only one. Looks like no one here knows when you’re supposed to use the Symlink libraries either.

symlink only places a symbolic link to the library into the xcode project. that way you don’t have it dublicated.
this is suitable when you build it locally

for backup and versioning usage you must build without symlink so the library is physically there cause the symlink might point to nowhere on other machines or even your own machine in the future (or at least not point to the right version)