I have tested this item ✅ successfully on 0607702

Code review.

Change is correct.

While we use American spelling for code names, e.g. variable or method names or keys of language string, the content should be British.

I have tested this item ✅ successfully on 0607702

RTC

✅ Final check before merge with grep -i '".*color.*"' administrator/language/en-GB/* language/en-GB/* before the PR the changed entries are found, with unpacking the PR full package the remaining places are OK as CSS or plugin-type:

aadministrator/language/en-GB/lib_joomla.ini:JLIB_DATABASE_ERROR_FUNCTION_FAILED="DB function failed with error number %s <br><span style=\"color: red;\">%s</span>"
administrator/language/en-GB/lib_joomla.ini:JLIB_JS_AJAX_ERROR_PARSE="A parse error has occurred while processing the following JSON data:<br><code style=\"color:inherit;white-space:pre-wrap;padding:0;margin:0;border:0;background:inherit;\">%s</code>"
administrator/language/en-GB/plg_fields_color.ini:PLG_FIELDS_COLOR_XML_DESCRIPTION="This plugin lets you create new fields of type 'color' in any extensions where custom fields are supported."
administrator/language/en-GB/plg_fields_color.sys.ini:PLG_FIELDS_COLOR_XML_DESCRIPTION="This plugin lets you create new fields of type 'color' in any extensions where custom fields are supported."
language/en-GB/lib_joomla.ini:JLIB_DATABASE_ERROR_FUNCTION_FAILED="DB function failed with error number %s <br><span style=\"color: red;\">%s</span>"
language/en-GB/lib_joomla.ini:JLIB_JS_AJAX_ERROR_PARSE="A parse error has occurred while processing the following JSON data:<br><code style=\"color:inherit;white-space:pre-wrap;padding:0;margin:0;border:0;background:inherit;\">%s</code>"

Thank you @brianteeman for your contribution. Thank you @tecpromotion and @richard67 for testing.