The color quite hard to read in command mode.

[hungpham3112]

I tried to debug the key mapping with :nmap

"Edge colorscheme settings
let g:edge_style = 'neon'
let g:edge_enable_italic = 0
let g:edge_disable_italic_comment = 1
let g:edge_lightline_disable_bold = 1

I don't know if problem caused by my config or those are default color. Thanks in advance.

[sainnhe]

That dim grey color is controlled by SpecialKey highlight group.

From :h hl-SpecialKey

SpecialKey  Unprintable characters: text displayed differently from what
        it really is. But not 'listchars' whitespace. |hl-Whitespace|

The original purpose of this hi groups is to control the color of listchars.

From :h 'listchars'

'listchars' 'lcs'   string  (default: "tab:> ,trail:-,nbsp:+"
                 Vi default: "eol:$")
            global or local to window |global-local|
    Strings to use in 'list' mode and for the |:list| command.  It is a
    comma separated list of string settings.

                            *lcs-eol*
      eol:c     Character to show at the end of each line.  When
            omitted, there is no extra character at the end of the
            line.
                            *lcs-tab*
      tab:xy[z] Two or three characters to be used to show a tab.
            The third character is optional.

      tab:xy    The 'x' is always used, then 'y' as many times as will
            fit.  Thus "tab:>-" displays:
                >
                >-
                >--
                etc.

      tab:xyz   The 'z' is always used, then 'x' is prepended, and
            then 'y' is used as many times as will fit.  Thus
            "tab:<->" displays:
                >
                <>
                <->
                <-->
                etc.

            When "tab:" is omitted, a tab is shown as ^I.

It's better to use dim grey in listchars, this design is also widely accepted by other color schemes.