caddy/caddytest/integration/caddyfile_adapt/tls_internal_options.txt

a.example.com {
	tls {
		issuer internal {
			ca foo
			lifetime 24h
			sign_with_root
		}
	}
}
----------
{
	"apps": {
		"http": {
			"servers": {
				"srv0": {
					"listen": [
						":443"
					],
					"routes": [
						{
							"match": [
								{
									"host": [
										"a.example.com"
									]
								}
							],
							"terminal": true
						}
					]
				}
			}
		},
		"tls": {
			"automation": {
				"policies": [
					{
						"subjects": [
							"a.example.com"
						],
						"issuers": [
							{
								"ca": "foo",
								"lifetime": 86400000000000,
								"module": "internal",
								"sign_with_root": true
							}
						]
					}
				]
			}
		}
	}
}