caddy/caddytest/integration/caddyfile_adapt/header.txt

:80 {
	header Denis "Ritchie"
	header +Edsger "Dijkstra"
	header ?John "von Neumann"
	header -Wolfram
	header {
		Grace: "Hopper"  # some users habitually suffix field names with a colon
		+Ray "Solomonoff"
		?Tim "Berners-Lee"
		defer
	}
}
----------
{
	"apps": {
		"http": {
			"servers": {
				"srv0": {
					"listen": [
						":80"
					],
					"routes": [
						{
							"handle": [
								{
									"handler": "headers",
									"response": {
										"set": {
											"Denis": [
												"Ritchie"
											]
										}
									}
								},
								{
									"handler": "headers",
									"response": {
										"add": {
											"Edsger": [
												"Dijkstra"
											]
										}
									}
								},
								{
									"handler": "headers",
									"response": {
										"require": {
											"headers": {
												"John": null
											}
										},
										"set": {
											"John": [
												"von Neumann"
											]
										}
									}
								},
								{
									"handler": "headers",
									"response": {
										"deferred": true,
										"delete": [
											"Wolfram"
										]
									}
								},
								{
									"handler": "headers",
									"response": {
										"add": {
											"Ray": [
												"Solomonoff"
											]
										},
										"deferred": true,
										"set": {
											"Grace": [
												"Hopper"
											]
										}
									}
								},
								{
									"handler": "headers",
									"response": {
										"require": {
											"headers": {
												"Tim": null
											}
										},
										"set": {
											"Tim": [
												"Berners-Lee"
											]
										}
									}
								}
							]
						}
					]
				}
			}
		}
	}
}