fortran code-remove the positions

I can’t analyze this statement.(~!!)
This code is part of frontal solver in FEM.
what does that mean NFUNC(0,JFRON)?
Is it possible it matrix 0 rows?
In accroding to text, that means
“removes the function of the global stiffness submatrix positions from the innermost expensive loop”

———————————————————
IF(KRESL.GT.1) GO TO 418
IF(EQUAT(JFRON,NBUFA).EQ.0.0) GO TO 270
NLOCA=NFUNC(0,JFRON) ~~~~~~~~~~~~!!
CUREQ=EQUAT(JFRON,NBUFA)
DO 260 LFRON=1,JFRON
NGASH=LFRON+NLOCA
260 GSTIF(NGASH)=GSTIF(NGASH)-CUREQ*EQUAT.
( LFRON,NBUFA). /PIVOT
418 CONTINUE
270 CONTINUE