abap/warn2error_release is a SAP Parameter attribute which is used to control Set syntax check release compatibility for warnings 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 .
Set start release for syntax warnings to be switched to syntax errors.
The handling of syntax warnings behaves compatible to the release set by
this profile parameter.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.