Meaning of the flags in the "fl" column

Option: 0 (0=show all flags, x=hexadecimal)

1 one of the coordinates had an excessively large χ2
2 row from PPMX (Cat. I/312) [if set, magnitudes b1, b2, r1, r2, i have a special meaning]
4 row from PPMX (Cat. I/312) (replaces a single USNO-B object)
8 row replaces multiple USNO-B1.0 objects