How do you get the name field of a JSON object in Powershell if you don't know it?
You can use $json.psobject.properties.name after it's converted:
@' { "CARD_MODEL_TITLE": "OWNER'S MANUAL", "CARD_MODEL_SUBTITLE": "Configure your download", "CARD_MODEL_SELECT": "Select Model", "CARD_LANG_TITLE": "Select Language", "CARD_LANG_DEVICE_LANG": "Your device", "CARD_YEAR_TITLE": "Select Model Year", "CARD_YEAR_LATEST": "(Latest)", "STEPS_MODEL": "Model", "STEPS_LANGUAGE": "Language", "STEPS_YEAR": "Model Year", "BUTTON_BACK": "Back", "BUTTON_NEXT": "Next", "BUTTON_CLOSE": "Close" }'@ | set-content jsonfile.json$json = (Get-Content "jsonfile.json" -Raw) | ConvertFrom-Json$json.psobject.properties.nameCARD_MODEL_TITLECARD_MODEL_SUBTITLECARD_MODEL_SELECTCARD_LANG_TITLECARD_LANG_DEVICE_LANGCARD_YEAR_TITLECARD_YEAR_LATESTSTEPS_MODELSTEPS_LANGUAGESTEPS_YEARBUTTON_BACKBUTTON_NEXTBUTTON_CLOSEYou can also eliminate the -join by using the -Raw switch with Get-Content