matrix-rust-sdk/test_data/events/message_edit.json

{
    "content": {
        "body": " * edited message",
        "m.new_content": {
            "body": "edited message",
            "msgtype": "m.text"
        },
        "m.relates_to": {
            "event_id": "some event id",
            "rel_type": "m.replace"
        },
        "msgtype": "m.text"
    },
    "event_id": "edit event id",
    "origin_server_ts": 1590262659984,
    "sender": "@alice:matrix.org",
    "type": "m.room.message",
    "unsigned": {
        "age": 85
    }
}