how do you read a dkim header?

https://www.emailonacid.com/blog/article/email-development/what_is_dkim_everything_you_need_to_know_about_digital_signatures

Here is an example DKIM signature (recorded as an RFC2822 header field) for the signed message:

DKIM-Signature a=rsa-sha1; q=dns;
d=example.com;
i=user@eng.example.com;
s=jun2005.eng; c=relaxed/simple;
t=1117574938; x=1118006938;
h=from:to:subject:date;
b=dzdVyOfAKCdLXdJOc9G2q8LoXSlEniSb
av+yuU4zGeeruD00lszZVoG4ZHRNiYzR

Let's take this piece by piece to see what it means. Each "tag" is associated with a value.

• b = the actual digital signature of the contents (headers and body) of the mail message
• bh = the body hash
• d = the signing domain
• s = the selector
• v = the version
• a = the signing algorithm
• c = the canonicalization algorithm(s) for header and body
• q = the default query method
• l = the length of the canonicalized part of the body that has been signed
• t = the signature timestamp
• x = the expire time
• h = the list of signed header fields, repeated for fields that occur multiple times