The info in this thread could be the starting point for this page: http://lists.debian.org/debian-mentors/2006/09/msg00223.html

What are binNMUs?

A binNMU is a binary-only non-maintainer upload. This is necessary when the build for a specific architecture failed, or produced buggy packages, due to a problem in the build environment itself (not due to an error in the package source). Such problems include library transitions (example) or a misconfiguration on the package maintainer's machine used for preparing uploads (example). In a binNMU, the arch: any packages are rebuilt, but the arch: all packages are not.

Each of the arch: any packages receives a new version number which is the old version number with the suffix +b appended plus a version number for the binNMU (e.g. version 2.3.4-3 will become 2.3.4-3+b1). The binNMU version is incremented independently on each architecture (example). The only file in the source package which is modified by the binNMU is debian/changelog, which gets a new entry for the new version. (Historically, binNMU version numbers were created by bumping (or creating, if it did not already exist) the third-level number in the Debian revision, for instance 2.3.4-3 would instead have become 2.3.4-3.0.1. This numbering convention is no longer used.)

Where to request a binNMU?

To request a binNMU for official architectures (except hurd-i386) ask on the debian-release mailing list.

Please read http://release.debian.org/wanna-build.txt for details on how a binNMU request should look like.

How to make packages binNMU safe?

Executive summary

only a potential problem for source packages that generate multiple binary packages
do not use the ${Source-Version} variable; this has been deprecated!
declaring dependency between 2 arch: any packages: ${binary:Version}
declaring dependency between an arch: any to an arch: all package: ${source:Version}
no way for a safe dependency between an arch: all to an arch: any package using these variables
- however, if only a minimum version is needed, one may use for instance Depends: foo-binary (>= ${source:Version})

Note: The versioned Build-Depends on dpkg-dev (>= 1.13.19) is not needed anymore, since Etch, Lenny and Sid all have the necessary version.

Example

For example, sometimes a package refers to the version of the source package in package relationship definitions. Consider a source package that still uses the deprecated ${Source-Version} variable:

 Source: foo
 
 Package: foo-bin
 Depends: foo-common (= ${Source-Version})
 Architecture: any
 
 Package: foo-common
 Architecture: all

The first upload creates the following versions:

Source package: foo 1.0-1
Architecture specific package: foo-bin 1.0-1 (Depends: foo-common 1.0-1)
Architecture independent package: foo-common 1.0-1

Now, suppose the foo-bin package is binNMU uploaded for an architecture. The ${Source-Version} variable is retrieved from debian/changelog, so after the binNMU the archive will contain the following versions:

Source package: foo 1.0-1
Architecture specific package: foo-bin 1.0-1+b1 (Depends: foo-common 1.0-1+b1)
Architecture independent package: foo-common 1.0-1

The foo-common package needs no new upload, because it was properly created before! However, there is no version 1.0-1+b1 of foo-common, so the dependencies are now broken, and foo-bin is uninstallable on the architecture where foo was binNMU'ed.

The solution is to use ${source:Version} instead of ${Source-Version}. This variable is also retrieved from the latest entry in the changelog, but any +b suffix is discarded. So, the following packages are created:

Source package: foo 1.0-1
Architecture specific package: foo-bin 1.0-1+b1 (Depends: foo-common 1.0-1)
Architecture independent package: foo-common 1.0-1