/usr/share/doc/gromacs/html/dev-manual/ is in gromacs-data 5.1.2-1ubuntu1.
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/usr/share/doc/gromacs/html/dev-manual/build-system.html
/usr/share/doc/gromacs/html/dev-manual/doxygen.html
/usr/share/doc/gromacs/html/dev-manual/formatting.html
/usr/share/doc/gromacs/html/dev-manual/gmxtree.html
/usr/share/doc/gromacs/html/dev-manual/includestyle.html
/usr/share/doc/gromacs/html/dev-manual/index.html
/usr/share/doc/gromacs/html/dev-manual/jenkins.html
/usr/share/doc/gromacs/html/dev-manual/naming.html
/usr/share/doc/gromacs/html/dev-manual/overview.html
/usr/share/doc/gromacs/html/dev-manual/relocatable-binaries.html
/usr/share/doc/gromacs/html/dev-manual/style.html
/usr/share/doc/gromacs/html/dev-manual/testutils.html
/usr/share/doc/gromacs/html/dev-manual/tools.html
/usr/share/doc/gromacs/html/dev-manual/uncrustify.html