/dev/characters/{character_id}/mail/{mail_id}/
/legacy/characters/{character_id}/mail/{mail_id}/
/v1/characters/{character_id}/mail/{mail_id}/
curl --location --request GET 'https://esi.evetech.net/latest/characters//mail//'
{
"body": "blah blah blah",
"from": 90000001,
"labels": [
2,
32
],
"read": true,
"subject": "test",
"timestamp": "2023-08-15T09:13:17.861Z"
}