ms/http_was_required is a SAP Parameter attribute which is used to control SAP Web AS with ABAP stack required for dispatching requests 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 a request is to be directed to a J2EE server, you can define that
only servers that also contain the ABAP stack are selected.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.