Version 1.8.0 of package Xref has just been released in GNU ELPA. You can now find it in M-x list-packages RET.
Xref describes itself as: ========================== Cross-referencing commands ========================== More at https://elpa.gnu.org/packages/xref.html ## Summary: This file provides a generic infrastructure for cross referencing commands, such as "find definition". The unique functionality is configured by defining an xref backend. That consists of a constructor function, and implementations for the generic functions (using `cl-defmethod'). The constructor should return a value that `cl-defmethod' can dispatch on. Most often it is a plain symbol, such as `elisp'. A major or minor mode would use `add-hook' to set itself up and add the backend constructor to `xref-backend-functions'. Some important backend methods to define are: `xref-backend-identifier-at-point', `xref-backend-identifier-completion-table', `xref-backend-definitions', `xref-backend-references', `xref-backend-apropos'. And more optional ones: ## Recent NEWS: [Not provided 🙁]
