Which information does the body of a cover letter include

The cover letter of any official letter should include the main positive points of the candidate.

Explanation:

It is best to try to put everything that will make it hard for the company to not hire you. In other words, you are selling yourself as the best candidate for the job to them and making sure that you got your best options available. So, an applicant's cover letter should give compact details about one's qualifications, what position one is applying for, why s/he should be hired and why s/he is the best candidate for the job.

faithful servants eumaeus and philaetius:

his ragged vest then drawn aside disclosed the sign conspicuous, and the scar exposed: eager they view'd, with joy they stood amazed with tearful eyes o'er all their master gazed:

these servants know ulysses by the scar he got when he was a child - so when he showed them the mark, they immediately knew this is truly their master and they hugged him, finally starting to believe his words.