The short answer is that if you map a compose key, you needn’t worry about dead keys.
<dead_tilde> etc. correspond to keys in the keymap which are “dead”, i.e. which don’t produce a character on their own but always combine with the next keystroke. For example, on French keyboards, there’s a ^ key to the right of P which allows you to produce “ê” etc., by pressing ^ e. These don’t need the compose key at all.
The compose key is used for mappings which start with
<Multi_key> (look at
/usr/share/X11/locale/en_US.UTF-8/Compose), and those use “normal” keys; for example,
<Multi_key> <asciicircum> <e> means that you press your compose key, then ^ (the non-dead variant), then
e, to get “ê”.
The standard accent compose sequences use the following keys for typical accents:
- , for a cedilla;
- ` for a grave accent;
- ' for an acute accent;
- ^ for a circumflex accent;
- " for a diaeresis;
- ~ for a tilde.
There are many, many more combinations, look at the
Compose file mentioned above for details.