Doing

    dpkg-repack --generate git-core

results in a dpkg-repack-NNN/usr/lib/git-core directory with separate
copies of the files from /usr/lib/git-core, whereas I hoped the repack
dir would preserve the hard links there.

/usr/lib/git-core has some 103 names for the same 1Mb file.  Letting
dpkg-repack make a deb,

    dpkg-repack git-core

results in a rather large 57Mb, where the original is about 5.5Mb. :-)