I found the following Ghostty config can be used to get i3wm border around Ghostty (using i3wm with XFCE)
window-decoration = true
gtk-titlebar = false
gtk-adwaita = false
Related: With the release of 1.0.1 of Ghostty, there is an issue with border around Ghostty on Linux
With version 1.1.0, the mentioned config for ghostty does not show i3wm border around ghostty.
get the border around ghostty
1.1.2
in i3wm using the following configgtk-adwaita = true gtk-titlebar = false window-decoration = server