This is due to some memory-management hackery in e291c75a95 (remote.c:
add branch_get_push, 2015-05-21). The good news is that not only is it
not too hard to untangle this, but it is closely related to leaks you
are seeing on your topic.

I'll post a series in a moment fixing both.

This seems to not have helped my memory leak. I squashed and applied your
commits on top of my work as a separate pull request on GitHub, the CI leak
tests are still failing:

https://github.com/git/git/pull/2170


Harald