Super-. Writes the character’e’ to any writing application, terminal, or Inkscape. If I press it again, the character disappears.
I first noticed this in emacs.
When I press M-. this gray popup opens up, and I can type inside it. Pressing enter will commit its contents to the buffer, M-. or Escape will make it disappear.
What is it? Does it have a name? It is preventing me to use this keybinding. Happens even when I run emacs as emacs -q
(no config). Picture below.