An '&' means 'turn the next line into keywords'. An '&' on line 1 would mean that a second line of keywords should be read in. If that second line contained an '&', then a third line of keywords would be read in. If the first line has an '&' then the first description line is omitted; if the second line also has an '&', then both description lines are omitted.
Examples: Use of one '&'
VECTORS DENSITY RESTART & NLLSQ T=1H SCFCRT=1.D-8 DUMP=30M PM3 FOCK OPEN(2,2) ROOT=3 SINGLET SHIFT=30 Test on a totally weird system
Use of two '&'s
LARGE=-10 & DRC=4.0 T=1H SCFCRT=1.D-8 DUMP=30M ITRY=300 SHIFT=30 PM3 OPEN(2,2) ROOT=3 SINGLET NOANCI T-PRIORITY=0.5 & LET GEO-OK VELOCITY KINETIC=5.0