abap/ext_debugging_possible is a SAP Parameter attribute which is used to control To restrict the usage of extern/HTTP debugging 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 .
You can use this profile parameter to restrict external/HTTP debugging
for external sessions.
Value 0
External debugging is allowed if the external user is a dialog or
service user.
Value 1
External debugging is allowed if the external user is a service user.
Value 2
External debugging is not allowed for external users.
See SAP Parameter Documentation for full SAP documentation for this profile parameter.