Install `hyperbole' for exploration

README.org

@@ -244,6 +244,7 @@ The [[info:emacs#Init File][init file (info)]] does not load the ~custom-file~ a
                  (embark . "gnu-devel")
                  (embark-consult . "gnu-devel")
                  (engrave-faces . "gnu")
+                 (hyperbole . "gnu-devel")
                  (marginalia . "gnu-devel")
                  (org . "gnu-devel")
                  ,(when (version< emacs-version "28.9.9")
@@ -264,6 +265,7 @@ The [[info:emacs#Init File][init file (info)]] does not load the ~custom-file~ a
    `,(delq nil `(async              ; asynchroneous processing
                  auctex             ; Aalborg University Center TeX
                  company            ; complete anything
+                 debbugs            ; access the GNU bug tracker
                  engrave-faces      ; convert font-lock to ANSI/HTML/LaTeX
                  magit              ; Git Text-based User Interface
                  no-littering       ; keep `user-emacs-directory' clean
@@ -5020,6 +5022,37 @@ Listing [[lst:configure-browse-url]] configures =browse-url=.
   (advice-add 'eww-display-pdf :around #'eww-display-pdf-as-binary))
 #+end_src
 
+*** [[https://www.gnu.org/software/hyperbole/][GNU Hyperbole]]
+:PROPERTIES:
+:CUSTOM_ID: sec:ensure-hyperbole-installation
+:END:
+
+#+caption[Ensure Hyperbole installation]:
+#+caption: Ensure Hyperbole installation.
+#+name: lst:ensure-hyperbole-installation
+#+begin_src emacs-lisp
+(when (ensure-package-installation 'hyperbole)
+  ;; Hyperbole's autoloads files break package.el's autoloading.
+  (dolist (name '("hyperbole-autoloads" "kotl-autoloads"))
+    (when-let (result (directory-files-recursively
+                       (expand-file-name package-user-dir)
+                       (concat name ".el\\'")))
+      (cl-pushnew (file-name-directory (car result))
+                  load-path :test #'string=)
+      (load name)))
+
+  (defun either-hyperbole-or-vertico-mode ()
+    "Toggle between either hyperbole-mode or vertical mode."
+    (interactive)
+    (when (and (boundp hyperbole-mode) (boundp vertico-mode))
+      (if hyperbole-mode
+          (progn
+            (hyperbole-mode -1)
+            (vertico-mode +1))
+        (hyperbole-mode +1)
+        (vertico-mode -1)))))
+#+end_src
+
 *** [[https://en.wikipedia.org/wiki/Media_type#Mailcap][Mailcap]]
 :PROPERTIES:
 :CUSTOM_ID: sec:mailcap