PAF (Personal Ancestral File)
Personal Ancestral File (PAF) was free genealogy software provided by FamilySearch, a website operated by The Church of Jesus Christ of Latter-day Saints.
PAF software up to v2 used individual .DAT file to store genealogical data. File names included, INDIV2.dat, MARR2.dat, NAME2.dat, NOTES2.dat, REPTITL2.dat, etc.
PAF software versions 3-5 used a single .PAF file to store data. The head for PAF files take up the first 14 bytes. Version 5 header starts with ascii
500 500 PAF
The first set of numbers indicates the last version of PAF to write to the file and the second set is oldest version of PAF that can read the file.