What does "$CICS ON" in a legacy IBM COBOL program mean?

Question

I have some IBM COBOL of 2006 vintage. It contains "$CICS ON" and "$CICS OFF". I'm generally familiar with IBM COBOL "EXEC CICS" statements and directives, but I've never seen this pair.

What do these commands do, and where are they documented (IBM reference manual name would be ideal answer)? Searching the web didn't show an obvious result.

COBOL program fragment below:

000750 01  WG-YOB.                                                              
000760     05  FILLER                  PIC X(4).                                
000770     05  WX-YOB                  PIC X(2).                                
000780$CICS ON.                                                                 
000790$CICS OFF.                                                                
000800$COPY CMPLDBF.                                                            
000810$COPY CMPLDBH.                                                            
000820 LINKAGE SECTION.                                                         
000830 01  DFHCOMMAREA.                                                         
000840 COPY COMMAREA.                                                           
000850 PROCEDURE DIVISION. 

EDIT: This is a code base of about 1000 programs ~~ 450K SLOC. The only $ commands I find across this entire code base are:

$CICS ON.
$CICS OFF.
$COPY <filename>.
$BLOCK.
$BlOCKS.
                                              

If it helps, the copy libs referenced by $COPY contain nonstandard COBOL declarations (note "COMMBLOCK" and "FORM" starting in column 7)

000100COMMBLOCK OF HCPDSDB.                                                     
000110 01 HCPDSDB-DB.                                                           
000120     05 RECORD-NAME.                                                      
000130     05 RETURN-KODE.                                                      
000140     05 FREE.                                                             
000150     05 LAST-RECORD-FLAG.                                                 
000160     05 PASSWD.                                                           
000170     05 NO-OF-RECORDS.
...   
000380FORM YYMMDD.                                                              
000390     05 C4-RED REDEFINES C4.                                              
000400        07  C4-YY      PIC 99.                                            
000410        07  C4-MM      PIC 99.                                            
000420        07  C4-DD      PIC 99.                                            
000430     05 C5             PIC 9(11).                                         
000440     05 C6             PIC 9(6).   

Answer 1

Converting comment to an answer at OP request.

May be System 2000 references. V1 PDF from 20+ years ago includes $CICS ON and $CICS OFF directives. I cannot locate any V2 documentation that includes these directives.

From comments, OP found a more helpful manual at https://support.sas.com/resources/papers/proceedings/pdfs/s2k/PLEX.pdf which "appears to contain all the $xxxx directives mentioned" in the question.

I'm glad I was able to at least point in a helpful direction.