https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116613
--- Comment #32 from Kamil Dudka <kdudka at redhat dot com> --- Thanks for the update! I confirm that the man page is readable now and that the use of -fdiagnostics-set-output= eliminated the duplicated output without the ugly workaround. I have also tried sarif:version=2.2-prerelease and in the basic testing scenario everything worked as expected.
