The ARB format is a JSON file containing an object where the keys are the
message ids and the values are the translations.
It is extensible because it can also contain metadata about each message.
For example:
```
{
"@@locale": "...",
"message-id": "Translated message string",
"@message-id": {
"type": "text",
"description": "Some description text",
"x-locations": [{ "start": {"line": 23, "column": 145}, "file": "some/file.ts" }]
},
}
```
For more information, see:
https://github.com/google/app-resource-bundle/wiki/ApplicationResourceBundleSpecification
PR Close#36795