/etc/oss4/conf/oss_usb.conf is in oss4-base 4.2-build2010-5ubuntu2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | # Open Sound System configuration file
# Remove the '#' in front of the option(s) you like to set.
#
#usb_trace=0
#
#usb_mixerstyle=1
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