This page gives pointers to various standards documentation that the GNU Development Chain complies on.

ELF/ABI	HTML	System V Application Binary Interface This documentation describes the ELF standard issued from the System V ABI. The ABI is maintained by SCO at http://www.sco.com/developer/devspecs/ .
DWARF2	PDF	DWARF Debugging Information Format This document is the Dwarf 2.0 specification published by Unix International. It specifies the symbolic debugging information format generated and understood by many compilers and debuggers. The Dwarf 2 standard is being revised by several companies like SGI, Red Hat and others. See Dwarf 2. (http://reality.sgi.com/davea_engr/objectinfo.html)
MALIS	PDF	Specification for Motorola 8- and 16-Bit Assembly Language Input Standard This document published by Motorola specifies the standard for the assembly language.
MEABI	PDF	Motorola 8- and 16-Bit Embedded Application Binary Interface This document published by Motorola specifies the EABI for embedded 8- and 16-bit micro-controllers. It is a supplement of the System V Application Binary Interface.

Note: The GNU Development chain also complies with other standards such as IEEE-754, ISO-IEC 90 (and soon ISO-IEC 99) but these documents are not freely available (need to pay).