GetInvolved and Donate Infobar advertising messages were introduced in LO 6.1/6.2. An ESC decision had GetInvolved be removed from 6.1.5 stable. At the same time they requested to "release-build-ize it for 6.2 & 6.3". In other words, developers don't want to see it while they are working on the code.

There was also some talk (bug 120271c2) about making it nice for corporations to have an easy switch to turn the nagware stuff off for their own builds, so worth considering how to accomplish that related task at the same time. Corporations would also want to remove the help-donate and perhaps the help-getinvolved menu options (although hiding those menu items in debug builds probably wouldn't be a good idea).

The 6.1.5 revert can be seen at https://gerrit.libreoffice.org/66158.

Code pointers given by Michael Meeks are
dnl ===================================================================
dnl Test whether build target is Release Build
dnl ===================================================================
AC_MSG_CHECKING([whether build target is Release Build])
if test "$enable_release_build" = "" -o "$enable_release_build" = "no"; then
AC_MSG_RESULT([no])
ENABLE_RELEASE_BUILD=
else
AC_MSG_RESULT([yes])
ENABLE_RELEASE_BUILD=TRUE
fi
AC_SUBST(ENABLE_RELEASE_BUILD)

This guy - and a quick change to the relevant makefile eg.

./writerfilter/CppunitTest_writerfilter_rtftok.mk-ifeq
($(DISABLE_CVE_TESTS),TRUE)
./writerfilter/CppunitTest_writerfilter_rtftok.mk-$(eval $(call
gb_CppunitTest_add_defs,writerfilter_rtftok,\
./writerfilter/CppunitTest_writerfilter_rtftok.mk: -DDISABLE_CVE_TESTS \
./writerfilter/CppunitTest_writerfilter_rtftok.mk-))
./writerfilter/CppunitTest_writerfilter_rtftok.mk-endif

And then clobber the setting in a compile conditional there would be good.