From Egmont Koblinger:
> In terminal emulation, apps have to be able to print something and
keep track of the cursor, whereas they by design have no idea of the
font being used. In many terminals the font can also be changed runtime
and it's absolutely not feasible to then rearrange the cells. In some
other cases there is no font at all (e.g. the libvterm headless terminal
emulation library, or a detached screen/tmux), or there are multiple
fonts at once (a screen/tmux attached from multiple graphical
emulators).

> The only way to do that is via some external agreement on the number
of cells, which is typically the Unicode EastAsianWidth, often accessed
via wcwidth(). It's not perfect (changes through Unicode versions, has
ambiguous characters, etc.) but is still the best we have.

> glibc's wcwidth() reports 1 for ambiguous width characters, so the de
facto standard is that in terminals they are narrow.

> If the glyph is wider then the terminal has to figure out what to do.
It could crop it (newer versions of Konsole, as far as I know), overflow
to the right (VTE), shrink it (Kitty I believe does this), etc.

See Also:
https://bugzilla.gnome.org/show_bug.cgi?id=767529
https://gitlab.freedesktop.org/terminal-wg/specifications/issues/9
https://www.unicode.org/reports/tr11/tr11-34.html

Salient point from proposed update to Unicode Standard Annex #11:
> Note: The East_Asian_Width property is not intended for use by modern
terminal emulators without appropriate tailoring on a case-by-case
basis.

Fixes #2066
Fixes #2375

Added theming support

Add rendering and appearance - global pages