debug_key_events = false

When set to true, each key event will be logged by the GUI layer as an INFO level log message on the stderr stream from wezterm. You will typically need to launch wezterm directly from another terminal to see this logging.

This can be helpful in figuring out how keys are being decoded on your system, or for discovering the system-dependent "raw" key code values.

config.debug_key_events = true

Produces logs like the following when typing ls: (artificially wrapped to make these docs more readable):

 2021-02-20T17:04:28.149Z INFO  wezterm_gui::gui::termwindow   > key_event 
   KeyEvent { key: Char('l'), modifiers: NONE, raw_key: None,
   raw_modifiers: NONE, raw_code: Some(46), repeat_count: 1, key_is_down: true }
 2021-02-20T17:04:28.605Z INFO  wezterm_gui::gui::termwindow   > key_event
   KeyEvent { key: Char('s'), modifiers: NONE, raw_key: None, raw_modifiers: NONE,
   raw_code: Some(39), repeat_count: 1, key_is_down: true }

The key event has a number of fields:

• key is the decoded key after keymapping and composition effects. For example Char('l') occurs when typing the l key and Char('L') occurs when doing the same but with SHIFT held down. It could also be one of the keycode identifiers listed in the Configuring Key Assignments section.
• modifiers indicates which modifiers are active after keymapping and composition effects. For example, typing l with SHIFT held down produces key: Char('L'), modifiers: NONE because the SHIFT key composed to produce the uppercase L.
• raw_key represents the key press prior to any keymapping/composition events. If raw_key would be the same as key then raw_key will be printed as NONE.
• raw_modifiers represents the state of the modifier keys prior to any keymapping or composition effects. For example, typeing l with SHIFT held down produces raw_modifiers: SHIFT.
• raw_code is the hardware-and-or-windowing-system-dependent raw keycode value associated with the key press. This generally represents the physical location of the key independent of keymapping.
• repeat_count is usually 1 but on some systems may be larger number to indicate that the key is being held down and that the system is synthesizing multiple key-presses based on the system key repeat settings.
• key_is_down indicates whether the key is being pressed or released. This will always be true when debug logging, as logging and key press handling is only triggered on key press events in wezterm.