pub fn default_shell() -> PathBufExpand description
The user’s default shell, as Ghostty picks it with no command set.
In a command-line environment, one with TERM_PROGRAM set, it is
$SHELL. Otherwise, such as an application opened from the Dock or
the Finder, $SHELL is whatever the launcher had, so the shell comes
from the user’s passwd entry instead. Then /bin/sh.
Windows has no $SHELL, and Ghostty does not run there, so it follows
herdr: the first pwsh.exe on PATH, as a full path, which is what
other Windows terminals prefer, else powershell.exe, which every
Windows has.