/usr/share/systemtap/tapset/macros.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 4 5 | // Return MAXSTRINGLEN
@define MAXSTRINGLEN
%(
%{ /* pure */ /* unprivileged */ MAXSTRINGLEN %}
%)
|