to empty.
- 'cpoptions'   flags: |cpo-_|
- 'eadirection' cannot be set to empty.
- 'exrc'        searches for ".nvim.lua", ".nvimrc", or ".exrc" files. The
                user is prompted whether to trust the file.
- 'fileformat'  cannot be set to empty.
- 'fillchars'   flags: "msgsep", "horiz", "horizup", "horizdown",
                "vertleft", "vertright", "verthoriz"
- 'foldcolumn'  supports up to 9 dynamic/fixed columns
- 'guicursor'   works in the terminal (TUI)
- 'inccommand'  shows interactive results for |:substitute|-like commands
                and |:command-preview| commands
- 'jumpoptions'
    - "view" tries to restore |mark-view| when moving through the jumplist.
    - "clean" removes unloaded buffers from the jumplist.
- the |jumplist|, |changelist|, |alternate-file| or using |mark-motions|.
- 'laststatus'  global statusline support
- 'mousemodel'  cannot be set to empty.
- 'mousescroll' amount to scroll by when scrolling with a mouse
- 'pumblend'    pseudo-transparent popupmenu
- 'scrollback'
- 'shortmess'
    - "F" flag does not affect output from autocommands.
    - "q" flag fully hides macro recording message.
- 'showcmdloc'  cannot be set to empty.
- 'signcolumn'  can show multiple signs (dynamic or fixed columns)
- 'statuscolumn' full control of columns using 'statusline' format
- 'statusline' default is exposed as a statusline expression.
- 'splitkeep'   cannot be set to empty.
- 'tabline'     middle-click on tabpage label closes tabpage,
                and %@Func@foo%X can call any function on mouse-click
- 'termpastefilter'
- 'ttimeout', 'ttimeoutlen' behavior was simplified
- 'winblend'    pseudo-transparency in floating windows |api-floatwin|
- 'winhighlight' window-local highlights

Performance:
- Signs are implemented using Nvim's internal "marktree" (btree) structure.
- Folds are not updated during insert-mode.

Providers:
- If a Python interpreter is available on your `$PATH`, |:python| and
  |:python3| are always available. See |provider-python|.

Shell:
- Shell output (|:!|, |:make|, …) is always routed through the UI, so it
  cannot "mess up" the screen. (You can still use "chansend(v:stderr,…)" if
  you want to mess up the screen :)
- Nvim throttles (skips) messages from shell commands (|:!|, |:grep|, |:make|)
  if there is too much output. No data is lost, this only affects display and
  improves performance. |:terminal| output is never throttled.
- |:!| does not support "interactive" commands. Use |:terminal| instead.
  (GUI Vim has a similar limitation, see ":help gui-pty" in Vim.)
- :!start is not special-cased on Windows.
- |system()| does not support writing/reading "backgrounded" commands. |E5677|

Signs:
- 'signcolumn' can show multiple signs.
- Signs are removed if the associated line is deleted.
- Signs placed twice with the same identifier in the same group are moved.

Startup:
- |-e| and |-es| invoke the same "improved Ex mode" as -E and -Es.
- |-E| and |-Es| read stdin as text (into buffer 1).
- |-es| and |-Es| have improved behavior:
    - Quits automatically, don't need "-c qa!".
    - Skips swap-file dialog.
    - Optimized for non-interactive scripts: disables swapfile, shada.
- |-l| Executes Lua scripts non-interactively.
- |-s| reads Normal commands from stdin if the script name is "-".
- Reading text (instead of commands) from stdin |--|:
    - works by default: "-" file is optional
    - works in more cases: |-Es|, file args

TUI:
                        *:set-termcap*
- Start Nvim with 'verbose' level 3 to show terminal capabilities: >
        nvim -V3
<
                        *'term'* *E529* *E530* *E531*
- 'term' reflects the terminal type derived from |$TERM| and other environment
  checks.  Use `:echo &term` to get its value. For debugging only; not
  reliable during startup.
  - Note: If you want to detect when Nvim is running in a terminal, use
    `has('gui_running')` |has()| or see |nvim_list_uis()| for an example of
    how to inspect the UI channel.
- "builtin_x"