Specifies alternative programs to use instead of curl, dput, debsign, dpkg-source, dpkg-buildpackage, dpkg-genbuildinfo, dpkg-genchanges, dpkg-query, sbuild, pbuilder, cowbuilder, gpg, ssh, dgit, git-debrebase, apt-get, apt-cache, git, gbp-pq, gbp-build, or mergechanges.
For dpkg-buildpackage, dpkg-genbuildinfo, dpkg-genchanges, dpkg-query, mergechanges and sbuild, this applies only when the program is invoked directly by dgit.
For dgit, specifies the command to run on the remote host when dgit rpush needs to invoke a remote copy of itself. (dgit also reinvokes itself as the EDITOR for dpkg-source --commit; this is done using argv[0], and is not affected by --dgit=).
gbp-build's value is used instead of gbp build or git-buildpackage. (The default is the latter unless the former exists on PATH.) gbp-pq's value is used instead of gbp pq. In both cases, unusually, the specified value is split on whitespace to produce a command and possibly some options and/or arguments.
For pbuilder and cowbuilder, the defaults are sudo -E pbuilder and sudo -E cowbuilder respectively. Like with gbp-build and gbp pq, the specified value is split on whitespace.
For ssh, the default value is taken from the DGIT_SSH or GIT_SSH environment variables, if set (see below). And, for ssh, when accessing the archive and dgit-repos, this command line setting is overridden by the git config variables dgit-distro.distro.ssh and .dgit.default.ssh (which can in turn be overridden with -c). Also, when dgit is using git to access dgit-repos, only git's idea of what ssh to use (eg, GIT_SSH) is relevant.