Lucene character ranges incl. non A-Za-z

Hello,

how does character ranges work? Does it only work from A to Z? For that matter, I figurerd those are not ASCII table since e.g. {code0 TO codez} doesn’t find code=. I am desperately trying to catch = specifically.

try double backslash escape. It works in playground at least

GET opensearch_dashboards_sample_data_flights/_search
{"query": {"regexp": {
  "OriginWeather": ".*\\&.*"
}},
  "_source": "OriginWeather"
}