Just use 'WezTerm' as title.

.wezterm.lua

@@ -30,4 +30,8 @@ config.window_padding = {
     top = 0,
 }
 
+wezterm.on('format-window-title', function(tab, pane, tabes, panes, config)
+    return 'WezTerm'
+end)
+
 return config