By the way, here is a simple way to test Magit without installing it in your
Emacs. However, you will need Eldev (external relative to Emacs).

1. Install Eldev (https://github.com/doublep/eldev#installation)

2. Check out Magit sources, e.g. to `~/git/magit'

3. Run `$ cd ~/git/magit/lisp' (I don't know why they have this layout)

4. Create file `Eldev-local' with the following contents (since the
project doesn't use Eldev, you have to do this manually):

(setf eldev-project-main-file "magit.el")
(eldev-use-package-archive 'gnu-elpa)
(eldev-use-package-archive 'melpa)

5. Run e.g. like this: `$ eldev emacs --eval "(magit-status-setup-buffer \"~/emacs\")" ',
assuming `~/emacs' is a Git checkout you work on.

Paul

On Sat, 27 Aug 2022 at 19:01, Paul Pogonyshev <pogonyshev@gmail.com> wrote:
There is no mode binding (`C-h k C-b' returns `backward-char'). I don't know
how to read this (result of showing the keymap in `describe-text-properties'
buffer; at step 1:

(keymap keymap
        (3 keymap
           (5 . magit-diff-edit-hunk-commit)
           (20 . magit-diff-trace-definition))
        (67 . magit-commit-add-log)
        (38 . magit-do-async-shell-command)
        (117 . magit-unstage)
        (115 . magit-stage)
        (97 . magit-apply)
        (remap keymap
               (magit-revert-no-commit . magit-reverse)
               (magit-delete-thing . magit-discard)
               (magit-visit-thing . magit-diff-visit-file))
        (24 keymap
            (97 . magit-add-change-log-entry)
            (53 keymap
                (return . magit-diff-visit-file-other-frame))
            (52 keymap
                (97 . magit-add-change-log-entry-other-window)
                (return . magit-diff-visit-file-other-window)))
        (C-return . magit-diff-visit-worktree-file)
        (10 . magit-diff-visit-worktree-file))

At step 2:

(keymap
 (3 keymap
    (94 keymap
        (108 . magit-smerge-keep-lower)
        (98 . magit-smerge-keep-base)
        (117 . magit-smerge-keep-upper)
        (13 . magit-smerge-keep-current)))
 keymap
 (3 keymap
    (5 . magit-diff-edit-hunk-commit)
    (20 . magit-diff-trace-definition))
 (67 . magit-commit-add-log)
 (38 . magit-do-async-shell-command)
 (117 . magit-unstage)
 (115 . magit-stage)
 (97 . magit-apply)
 (remap keymap
        (magit-revert-no-commit . magit-reverse)
        (magit-delete-thing . magit-discard)
        (magit-visit-thing . magit-diff-visit-file))
 (24 keymap
     (97 . magit-add-change-log-entry)
     (53 keymap
         (return . magit-diff-visit-file-other-frame))
     (52 keymap
         (97 . magit-add-change-log-entry-other-window)
         (return . magit-diff-visit-file-other-window)))
 (C-return . magit-diff-visit-worktree-file)

Paul
 (10 . magit-diff-visit-worktree-file))

On Sat, 27 Aug 2022 at 18:56, Eli Zaretskii <eliz@gnu.org> wrote:
> From: Paul Pogonyshev <pogonyshev@gmail.com>
> Date: Sat, 27 Aug 2022 18:32:15 +0200
> Cc: Gerd Möllmann <gerd.moellmann@gmail.com>,
>       57433@debbugs.gnu.org
>
> > Now, I put the point at the beginning of the third line ([^] is the point):
>
> Text content at position 32867:
>
> There is an overlay here:
>  From 32867 to 32901
>   evaporate            t
>   font-lock-face       magit-diff-file-heading-highlight
>
> There are text properties here:
>   font-lock-face       magit-diff-file-heading
>   keymap               [Show]
>   magit-section        [Show]

Maybe the 'keymap' part?  Could it be that C-b has a binding in that
keymap?