How to decode base64 + rsa including root ca in der format?

Question

iOS

I read the Wiki , which shows what data is encoded and what.

My task: To understand from what the data is formed FairPlayCertChain
For this purpose first of all it is necessary to decode them.

The data itself:

spoiler

MIICxDCCAi2gAwIBAgINMzOvBwQCrwACrwAABzANBgkqhkiG9w0BAQUFADB7MQswCQYD
    VQQGEwJVUzETMBEGA1UEChMKQXBwbGUgSW5jLjEmMCQGA1UECxMdQXBwbGUgQ2VydGlm
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    MAkGA1UEBhMCVVMxEzARBgNVBAoTCkFwcGxlIEluYy4xFzAVBgNVBAsTDkFwcGxlIEZh
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    BAsTHUFwcGxlIENlcnRpZmljYXRpb24gQXV0aG9yaXR5MS8wLQYDVQQDEyZBcHBsZSBG
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    ZCB0ZXJtcyBhbmQgY29uZGl0aW9ucyBvZiB1c2UsIGNlcnRpZmljYXRlIHBvbGljeSBh
    bmQgY2VydGlmaWNhdGlvbiBwcmFjdGljZSBzdGF0ZW1lbnRzLjANBgkqhkiG9w0BAQUF
    AAOCAQEAXDaZTC14t+2Mm9zzd5vydtJ3ME/BH4WDhRuZPUc38qmbQI4s1LGQEti+9HOb
    7tJkD8t5TzTYoj75eP9ryAfsfTmDi1Mg0zjEsb+aTwpr/yv8WacFCXwXQFYRHnTTt4sj
    O0ej1W8k4uvRt3DfD0XhJ8rxbXjt57UXF6jcfiI1yiXV2Q/Wa9SiJCMR96Gsj3OBYMYb
    WwkvkrL4REjwYDieFfU9JmcgijNq9w2Cz97roy/5U2pbZMBjM3f3OgcsVuvaDyEO2rpz
    GU+12TZ/wYdV2aeZuTJC+9jVcZ5+oVK3G72TQiQSKscPHbZNnF5jyEuAF1CqitXa5PzQ
    CQc3sHV1IQ==

According to the Wiki they are encoded like this: "(base64-encoded RSA certificate chain including root CA in DER format)".

Tell me how to decode?
Base64 + RSA as I understand it, Public Key and Private Key are needed.

It turns out that through services like this you can decode knowing the public key and private key?

Further about root ca in DER format, I did not understand at all.

If you need a public key and a private key, then maybe someone knows where to find them? I know that people somehow generate these same ones FairPlayCertChain, so someone was able to decode read / change and encode back ..?