EDIT: Nope.
As opposed to regular dash: -
Hitting the button to the right of [0] outputs a hyphen ("-"). Holding alt/option when hitting it will output an en dash ("–"), holding both alt/option and shift will output an em dash ("—").
- = -
⌥- = –
⇧⌥- = —
https://www.x.org/releases/X11R7.7/doc/libX11/i18n/compose/e...
For example, em dash is Compose+minus+minus+minus, en dash is Compose+minus+minus+period.
It's also useful for foreign glyphs like Compose+a+a for the Nordic å, Compose+s+s for German ß (with Shift it becomes ẞ, which the new German orthography rules officially recognise!), Compose+quote+<vowel> for the various umlauts and Compose+i+period for the dotless ı (with Shift it becomes the dotted İ).
For example (<^>! means the AltGr key):
<^>!4::Send „
<^>!5::Send “
<^>!2::Send ‚
<^>!3::Send ‘
<^>!+6::Send “
<^>!+7::Send ”
<^>!+8::Send ‘
<^>!+9::Send ’
<^>!-::Send –
<^>!.::Send …
Also to use Caps Lock as another Control key: Capslock::Ctrl
Or make windows stay on top of others, if even they lose focus: <^>!t::Winset, Alwaysontop, TOGGLE, A