rdisp/wp_no_spo_Fro_max is a SAP Parameter attribute which is used to control Maximum number of spool workprocesses used for frontend printing information. This is available within R/3 SAP systems depending on the version and release level.
Below is the standard documentation available and a few details of the attributes values .
If frontend printing is done by the spool service, the number of (spool)
workprocesses used for processing frontend jobs can be limited to keep
the regular spool service available even if there is a heavy load
produced by frontend jobs. This is necessary not to disturb the server
assignment for devices done because of the output classification. The
default is 1.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.