Knowledge of a person, place, subject, or activity because you have seen, used, or learned about it before.
She has a good familiarity with local customs.
His familiarity with computers helped him find a job.
Use familiarity with, not familiarity of, when you mean knowledge of a subject or activity.
Common phrases & grammar
familiarity with a subject · familiarity with local customs · a good familiarity with · familiarity with computers
familiarity with + noun
a familiarity with + noun