eu/iwb/server_win16 is a SAP Parameter attribute which is used to control Info Workbench: HTTP server for Help on Win16 platforms 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 .
The parameter specifies the host name of the HTTP server for Extended
Help when Windows 16-bit front ends are used. You only need to maintain
this parameter if help type 2 (PlainHtmlHttp) or 4 (HtmlHelpHttp) is
used.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.