Stylelint does not provide an error code for their warnings. Instead, it shows a string, which can be attached to https://stylelint.io/user-guide/rules/list/ for additional explanation.
Example:
base_url = "https://stylelint.io/user-guide/rules/list/"
error_name = "font-family-name-quotes"
$BROWSER "$base_url$error_name"
# firefox https://stylelint.io/user-guide/rules/list/font-family-name-quotes/