/usr/share/systemtap/tapset/linux/context.stpm is in systemtap-common 2.6-0.2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 | @define __context_unwind_error(depth) %(
error(sprint("reached end of stack before unwinding to level ", @depth))
%)
|