diff --git a/lisp/auth-source.el b/lisp/auth-source.el
index 1e0cde75583..d445c339571 100644
--- a/lisp/auth-source.el
+++ b/lisp/auth-source.el
@@ -2515,8 +2515,6 @@ Adapt also mode line."
         (read-passwd--hide-password)))))
 
 (defvar read-passwd-map
-  ;; BEWARE: `defconst' would purecopy it, breaking the sharing with
-  ;; minibuffer-local-map along the way!
   (let ((map (make-sparse-keymap)))
     (set-keymap-parent map minibuffer-local-map)
     (define-key map "\C-u" #'delete-minibuffer-contents) ;bug#12570
diff --git a/lisp/emacs-lisp/eldoc.el b/lisp/emacs-lisp/eldoc.el
index aa1871ac482..f412a38d6f5 100644
--- a/lisp/emacs-lisp/eldoc.el
+++ b/lisp/emacs-lisp/eldoc.el
@@ -154,7 +154,6 @@ this file since the obarray is initialized at load time.
 Remember to keep it a prime number to improve hash performance.")
 
 (defvar eldoc-message-commands
-  ;; Don't define as `defconst' since it would then go to (read-only) purespace.
   (obarray-make eldoc-message-commands-table-size)
   "Commands after which it is appropriate to print in the echo area.
 ElDoc does not try to print function arglists, etc., after just any command,
@@ -166,7 +165,6 @@ directly.  Instead, use `eldoc-add-command' and `eldoc-remove-command'.")
 
 ;; Not a constant.
 (defvar eldoc-last-data (make-vector 3 nil)
-  ;; Don't define as `defconst' since it would then go to (read-only) purespace.
   "Bookkeeping; elements are as follows:
   0 - contains the last symbol read from the buffer.
   1 - contains the string last displayed in the echo area for variables,