How to interpret the org-mode-map key binding?

Question

From the docs https://org-roam.readthedocs.io/en/master/ecosystem/, org-mode-map has binding for s-Y

(use-package org-download
  :after org
  :bind
  (:map org-mode-map
        (("s-Y" . org-download-screenshot)
         ("s-y" . org-download-yank))))

What does s-Y mean ? org-mode-map displays a number.

(keymap
 (8388729 . org-download-yank)
 (...)

To which key is org-download-yank bound?

Answer 1

1. Modifier key s- is called "Super". (event-modifiers 's-Y) returns (super), which says that s-Y uses (only) the super modifier.

   See the Emacs manual, node Modifier Keys. What physical keyboard key, if any, might correspond to this logical modifier key depends on your system and hardware.

2. (event-convert-list '(super ?y)) returns 8388729, which is the internal representation of the event produced by key s-Y. (kbd "s-Y") returns [8388729], which is the internal representation of the key s-Y.

   In my setup, and (describe-key [8388729]) returns the key-description string "s-Y is undefined". But presumably if you use org-roam that sexp will tell you what command s-Y is bound to in Org mode using org-roam.

Answer 2

[Transferred my comment to an answer after @Drew's encouragement, although I think most of it is included already in his (much more comprehensive) answer.]

s- is the Super key (usually the Windoze key on many keyboards, except for Macs). So assuming you installed the org-download package with the use-package stanza you indicated in your question, org-download-yank should be accessible by pressing and holding the Super key and pressing y. OTOH, it sometimes happens that the desktop manager intercepts that key for its own purposes and does not let emacs see it, in which case, you'll have to bind the command to a key that emacs can see: YMMV.