Header Editor config to allow loading Fira Code font on github.com and gitlab.com, see https://medium.com/@sportebois/how-to-make-online-code-easier-to-read-with-custom-font-with-ligatures-d6daa2c89325

HE_Content-Security-Policy Extensions

{
	"request": [],
	"sendHeader": [],
	"receiveHeader": [
		{
			"enable": true,
			"name": "Fira Code",
			"ruleType": "modifyReceiveHeader",
			"matchType": "regexp",
			"pattern": "^http[s]*:\\/\\/(?:[^/\\.]+\\.)*(?:github\\.com|gitlab\\.com)\\/",
			"exclude": "",
			"group": "Content-Security-Policy Extensions",
			"isFunction": true,
			"code": "// Rule for https://medium.com/@sportebois/how-to-make-online-code-easier-to-read-with-custom-font-with-ligatures-d6daa2c89325\n\nconst cspHeader = Object\n  .values(val)\n  .find((header) => header.name.toLowerCase() === 'content-security-policy')\n\nif (cspHeader) {\n  cspHeader.value = cspHeader.value\n    .replace(/(connect-src[^;]*)/, '$1 https://cdn.rawgit.com/tonsky/FiraCode/')\n    .replace(/(style-src[^;]*)/, '$1 https://cdn.rawgit.com/tonsky/FiraCode/')\n    .replace(/(font-src[^;]*)/, '$1 https://cdn.rawgit.com/tonsky/FiraCode/')\n}\n\n"
		}
	],
	"receiveBody": []
}