rdisp/plugin_auto_logout is a SAP Parameter attribute which is used to control Maximum time of no action for plugins (HTTP, ..) 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 the user context of an external plugin (for example, HTTP) was
stopped and there is no action for rdisp/plugin_auto_logout seconds,
then the context is automatically closed down. If the parameter has the
value 0, no automatic deletion of the context takes place.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.