Convert SBF to VCF

Unfortunately, there seems to exist no direct and reliable way of extracting contacts from a .sbf Android backup, which contains complete image of the phone, not just the contacts and user data. The only feasible way would most likely be to restore it on the original phone, and then sync the contacts with Google account. After that you can export your contacts from there. Otherwise sbf to vcf conversion seems highly unlikely.

Simply put, it is impossible to convert SBF to VCF directly.
Thus, there is no so-called sbf to vcf converter or a free online .sbf to .vcf converter to be found.