Gtk.Entry:invisible-char

"invisible-char"             Number                : Read / Write

The invisible character is used when masking entry contents (in \"password mode\")"). When it is not explicitly set with the Gtk.Entry:invisible-char property, GTK+ determines the character to use from a list of possible candidates, depending on availability in the current font.

This style property allows the theme to prepend a character to the list of candidates.

Since 2.18