[2] 値は X.501 Name です >>1。
[3] 証明書の TBSCertificate の欄の1つです。
TBSCertificate
[4] インターネット電子メールアドレス、DNS名、IPアドレス、URI を subject とする時は、 SAN も使わなければなりません >>5。
[6] (2014-11-01 05:54:38 +09:00 版) <https://cabforum.org/wp-content/uploads/BRv1.2.3.pdf#page=11>
Issuing CA: In relation to a particular Certificate, the CA that issued the Certificate. This could be either a RootCA or a Subordinate CA.
Issuing CA: In relation to a particular Certificate, the CA that issued the Certificate. This could be either a Root
CA or a Subordinate CA.