Man pages matching name probe::ioscheduler_trace.unplug_timer in section 3stap:

probe::ioscheduler_trace.unplug_timer.3stap.en	debian 10 / systemtap-doc
probe::ioscheduler_trace.unplug_timer.3stap.en	debian 11 / systemtap-doc
probe::ioscheduler_trace.unplug_timer.3stap.en	debian 12 / systemtap-doc