Variable: comment-indent-function
comment-indent-function is a variable defined in newcomment.el.gz.
Documentation
Function to compute desired indentation for a comment.
This function is called with no args with point at the beginning
of the comment's starting delimiter and should return either the
desired column indentation, a range of acceptable
indentation (MIN . MAX), or nil.
If nil is returned, indentation is delegated to indent-according-to-mode.
Probably introduced at or before Emacs version 26.1.
Source Code
;; Defined in /usr/src/emacs/lisp/newcomment.el.gz
;;;###autoload
(defvar comment-indent-function 'comment-indent-default
"Function to compute desired indentation for a comment.
This function is called with no args with point at the beginning
of the comment's starting delimiter and should return either the
desired column indentation, a range of acceptable
indentation (MIN . MAX), or nil.
If nil is returned, indentation is delegated to `indent-according-to-mode'.")