Original code is here.
I modify some codes to make this tool can be used on vanilla emacs. I am satisfied with this package, but it may not be suitable for everyone.
This package is extract from doom-emacs, so the usage is same, but has fewer commands to bind keys:
+lookup/definition+lookup/references+lookup/file
For the comprehensive configuration, look for the document of doom-emacs lookup module.
Thanks for doom-emacs!