I wanted to know when a certain identifier was introduced in goffice.
It turned out that it was fairly simple:
git grep -w GO_FORMAT_MARKUP `git tag -l 'GOFFICE*'` -- '*.h'
That commands searches all .h files from all Goffice releases.
It is very fast: about 0.5s (cpu time) on a fairly slow machine.
How do I do that with SVN?