reproduce some notes regarding terminal emulators

TERMS.md

@@ -1,15 +1,29 @@
 # Terminals and `TERM`
 
-| Terminal | Recommended `TERM` | Notes |
+With the wrong environment settings, programs can't properly control
+your terminal. It is critical that the `TERM` environment variable be
+correct for your shell, and that the terminfo database entry keyed
+by this variable be up-to-date. Furthermore, for 24-bit TrueColor, it
+is necessary to either use a `-direct` variant of your terminfo
+entry, or to declare `COLORTERM=24bit`. The latter instruct Notcurses
+to use 24-bit escapes regardless of advertised support. If you define
+this variable, and your terminal doesn't actually support these sequences,
+you're going to have a bad time.
+
+The following have been established on a Debian Unstable workstation.
+
+| Terminal | Recommended environment | Notes |
 | -------- | ------ | ----- |
-| Linux console | `linux` | 8 (512 glyph fonts) or 16 (256 glyph fonts) colors max. |
+| Linux console | `TERM=linux` | 8 (512 glyph fonts) or 16 (256 glyph fonts) colors max. |
 | FBterm | | |
-| kmscon | | |
-| XTerm | | |
-| XFCE4 Terminal | | |
-| Gnome Terminal | | |
-| Konsole | | |
-| Alacritty | | |
-| Kitty | | |
-| GNU Screen | `screen-256colors` | Must be compiled with `--enable-256color`. |
+| kmscon | `TERM=xterm-256color` | No RGB color AFAICT, nor any distinct terminfo entry. |
+| XTerm | `TERM=xterm-256color` `COLORTERM=24bit` | Must configure with `--enable-direct-color`. `TERM=xterm-direct` seems to have the undesirable effect of mapping low RGB values to a palette; I don't yet understand this well. The problem is not seen with the specified configuration. |
+| XFCE4 Terminal | `TERM=xfce` `COLORTERM=24bit` | No `xfce-direct` variant exists |
+| Gnome Terminal | `TERM=gnome` `COLORTERM=24bit` | |
+| Konsole | `TERM=konsole-direct` | |
+| Alacritty | `TERM=alacritty` `COLORTERM=24bit` | |
+| Kitty | `TERM=kitty-direct` | |
+| Sakura | `TERM=vte-256color` `COLORTERM=24bit` | |
+| st | `TERM=st-256color` `COLORTERM=24bit` | |
+| GNU Screen | `TERM=screen-256colors` | Must be compiled with `--enable-256color`. |
 | tmux | | |