This README list flag files that can be written in /etc/runit/ and their effect:
 
* /etc/runit/verbose
     Start/stop messages from runscripts, when they are written to do so
     Some extra message from maintainerscripts
     Some extra message from cpsv tool

* /etc/runit/debug
     Print the exit code of the run file of services, when finish-exec or similar
     code is used
     May print debug messages from maintainerscripts or cpsv

* /etc/runit/default.runsvdir
     During the boot sequence, when this file contains the basename of a
     directory in /etc/runit/runsvdir/, runsvdir will start monitoring such
     directory instead of 'default'

* /etc/runit/nosync
     Do no invoke 'sync' during the shutdown sequence
     
* /etc/runit/no.emulate.sysv
     Skip all sysv scripts enabled in rc2.d during the boot sequence, even if
     there is no correspondent native runscript in /etc/sv/

* /etc/runit/lsb.runit.sysv
     Turn off /lib/lsb/init-functions.d/40-runit : initscripts will be run unconditionally
     regardless the existence of a correspondent native runscript.

* /etc/runit/lsb.runit.mask
     Maks init sysv initscripts when a correspondent runscript exists, but
     do not forward signals (start|stop|restart) to the native runscript.

* /etc/runit/native.boot.run
      If this file exists and /etc/runit/boot-run is a directory, scripts with
      .sh exstension inside /etc/runit/boot-run/ are used for the boot
      sequence in stage 1 instead of default scripts inside /etc/rcS.d
      If the 'bootrun=1' variable is set in the kernel command line it
      has the same effect as the 'native.boot.run file: this is intended
      for testing new boot set of scripts.
      
      If this file exists and /etc/runit/shutdown-run is a directory, scripts
      with .sh extension inside /etc/runit/shutdown-run/ are ruse for the
      shutdown sequence in stage 3 in place of default scripts inside
      /etc/rc0.d or /etc/rc6.d/