I installed retext 6.0.0-lp150.2.3.1 on my Leap 15 system and tried to use it
to read the redis README.markdown file. It briefly displays a window then
crashes with a core dump.

$ retext /usr/share/doc/packages/php7-redis/README.markdown
Using configuration file: /home/dhoworth/.config/ReText project/ReText.conf
Process Process-1:
Traceback (most recent call last):
  File "/usr/lib64/python3.6/multiprocessing/process.py", line 258, in
_bootstrap
    self.run()
  File "/usr/lib64/python3.6/multiprocessing/process.py", line 93, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib/python3.6/site-packages/ReText/converterprocess.py", line 57,
in _converter_process_func
    current_markup = markup_class(job['filename'])
  File "/usr/lib/python3.6/site-packages/markups/markdown.py", line 146, in
__init__
    self._apply_extensions()
  File "/usr/lib/python3.6/site-packages/markups/markdown.py", line 132, in
_apply_extensions
    self.md = self.markdown.Markdown(extensions=extensions_final,
output_format='html4')
  File "/usr/lib64/python3.6/site-packages/markdown/core.py", line 100, in
__init__
    configs=kwargs.get('extension_configs', {}))
  File "/usr/lib64/python3.6/site-packages/markdown/core.py", line 126, in
registerExtensions
    ext = self.build_extension(ext, configs.get(ext, {}))
  File "/usr/lib64/python3.6/site-packages/markdown/core.py", line 166, in
build_extension
    module = importlib.import_module(ext_name)
  File "/usr/lib64/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 994, in _gcd_import
  File "<frozen importlib._bootstrap>", line 971, in _find_and_load
  File "<frozen importlib._bootstrap>", line 953, in _find_and_load_unlocked
ModuleNotFoundError: No module named
'markups.mdx_mathjax(enable_dollar_delimiter=False)'
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/ReText/tab.py", line 233, in
updatePreviewBox
    self.converted = self.converterProcess.get_result()
  File "/usr/lib/python3.6/site-packages/ReText/converterprocess.py", line 136,
in get_result
    status, converted = receiveObject(self.conn)
  File "/usr/lib/python3.6/site-packages/ReText/converterprocess.py", line 24,
in receiveObject
    sizeBuf = recvall(sock, 4)
  File "/usr/lib/python3.6/site-packages/ReText/converterprocess.py", line 17,
in recvall
    raise EOFError('Received 0 bytes from socket while more bytes were
expected. Did the sender process exit unexpectedly?')
EOFError: Received 0 bytes from socket while more bytes were expected. Did the
sender process exit unexpectedly?
Aborted (core dumped)

Sorry, I don't know where core files are put these days, if anywhere. Hopefully
the program will crash for you too and you can obtain your own.