ValueError: 'TARGET' is not a color!

[swedneck]

xonfig

+------------------+---------------------+
| xonsh            | 0.9.18              |
| Git SHA          | 26475146            |
| Commit Date      | May 5 06:42:28 2020 |
| Python           | 3.7.7               |
| PLY              | 3.11                |
| have readline    | True                |
| prompt toolkit   | 3.0.5               |
| shell type       | prompt_toolkit      |
| pygments         | 2.6.1               |
| on posix         | True                |
| on linux         | True                |
| distro           | fedora              |
| on darwin        | False               |
| on windows       | False               |
| on cygwin        | False               |
| on msys2         | False               |
| is superuser     | False               |
| default encoding | utf-8               |
| xonsh encoding   | utf-8               |
| encoding errors  | surrogateescape     |
+------------------+---------------------+

Expected Behavior

Xonsh should support the target color in $LS_COLORS

Current Behavior

Traceback (if applicable)

Traceback (most recent call last):
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/__amalgam__.py, line 24210, in main
    return main_xonsh(args)
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/__amalgam__.py, line 24239, in main_xonsh
    shell.shell.cmdloop()
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/ptk_shell/shell.py, line 197, in cmdloop
    line = self.singleline(auto_suggest=auto_suggest)
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/ptk_shell/shell.py, line 101, in singleline
    self.styler.style_name = env.get(XONSH_COLOR_STYLE)
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/__amalgam__.py, line 17732, in styler
    self._styler = XonshStyle(env.get(XONSH_COLOR_STYLE))
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/pyghooks.py, line 345, in __init__
    self.style_name = style_name
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/pyghooks.py, line 384, in style_name
    color_token = color_token_by_name(xonsh_color, self.styles)
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/pyghooks.py, line 223, in color_token_by_name
    pc = color_name_to_pygments_code(xc[0], styles)
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/pyghooks.py, line 143, in color_name_to_pygments_code
    if token in styles:
  File /usr/lib64/python3.7/collections/__init__.py, line 931, in __contains__
    return any(key in m for m in self.maps)
  File /usr/lib64/python3.7/collections/__init__.py, line 931, in <genexpr>
    return any(key in m for m in self.maps)
  File /usr/lib64/python3.7/_collections_abc.py, line 666, in __contains__
    self[key]
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/pyghooks.py, line 312, in __getitem__
    value = code_by_name(name, self.styles)
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/pyghooks.py, line 205, in code_by_name
    code = color_name_to_pygments_code(fg, styles)
  File /home/tim/.xonsh/lib64/python3.7/site-packages/xonsh/pyghooks.py, line 147, in color_name_to_pygments_code
    raise ValueError(!r is not a color!.format(name))
ValueError: 'TARGET' is not a color!
Xonsh encountered an issue during launch
Failback to /bin/sh

Steps to Reproduce

• run LS_COLORS='ln=target' xonsh in bash

[laloch]

Thanks for reporting, @swedneck!
I can confirm the issue. It was supposed to be fixed by #3255, but apparently was not.